初識50個Linux命令

本文轉載自查看原文 2016-05-08 11:40 5604 Linux/ linux

1. 【命令】：cat

【功能說明】：

concatenate files and print on the standard output ＃連接文件並打印到標准輸出，有標准輸出的都可以用重定向定向導入到文件里面

【語法格式】：

cat [OPTION]...[FILE]...

【選項參數】：

參數	說明	簡解
-b,--number-nonblank	number nonempty output lines	非空輸出行編號
-n,--number	number all outputnlines	所有行輸出編號

【示例】：

1、基本用法：查看文件內容

[root@oldboy ~]# cat /etc/passwd

root:x:0:0:root:/root:/bin/bash

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

2、把log1.txt的文件內容加上行號輸入log2.txt這個文件里

[root@oldboy ~]# cat -n log1.txt

1 2012-1

2 2013-1

3 2014-1

[root@oldboy ~]# cat -n log1.txt>log2.txt

[root@oldboy ~]# cat log2.txt

1 2012-1

2 2013-1

3 2014-1

3、把文件log1.txt里面的文件空格不顯示行號加入log2.txt中

[root@oldboy ~]# cat -n log1.txt

1 2012-1

2 2013-1

3 2014-1

[root@oldboy ~]# cat -b log1.txt

1 2012-1

2 2013-1

3 2014-1

[root@oldboy ~]# cat -b log1.txt>log2.txt

[root@oldboy ~]# cat log2.txt

1 2012-1

2 2013-1

3 2014-1

4、同時顯示log1.txt和log2.txt

[root@oldboy ~]# cat log1.txt log2.txt

2012-1

2013-1

2014-1

1 2012-1

2 2013-1

3 2014-1

5、使用cat編輯文檔內容

[root@oldboy ~]# cat >log1.txt<<EOF

> 2012-3

> 2013-3

> 2014-3

> EOF

[root@oldboy ~]# cat log1.txt

2012-3

2013-3

2014-3

6、使用cat追加編輯文檔內容

[root@oldboy data]# cat >>oldboy.txt<<EOF

> ni hao

> jin tian tian qi zhen hao

> EOF

[root@oldboy data]# cat oldboy.txt

I am oldboy

I am study linux

ni hao

jin tian tian qi zhen hao

2. 【命令】：cd

【功能說明】：

Change the current directory to DIR ＃更改當前路徑為DIR

【語法格式】：

cd [-L|-P] [dir]

【選項參數】：

參數	說明	簡解
-L	force symbolic links to be followed
-P	use the physical directory structure without following symbolic
-

【示例】：

[root@oldboy ~]# cd /

[root@oldboy /]#

[root@oldboy ~]# cd ..

[root@oldboy /]#

[root@oldboy /]# cd -

/root

[root@oldboy ~]#

3. 【命令】：mkdir

【功能說明】：

make directories ＃創建目錄

【語法格式】：

mkdir [OPTION]... DIRECTORY...

【選項參數】：

參數	說明	簡解
-m, --mode	set file mode (as in chmod), not a=rwx - umask	設定權限<模式>（類似chmod），而不是rwxrwxrwx減umask
-p, --parents	no error if existing, make parent directories as needed	遞歸創建目錄
-v, --verbose	print a message for each created directory	每次創建新目錄都顯示信息
-Z	set the SELinux security context of each created directory to CTX

【示例】：

1、基本用法：創建目錄

[root@oldboy ~]# mkdir /data

[root@oldboy ~]# cd /data

[root@oldboy data]# pwd

/data

2、遞歸創建多個目錄

[root@oldboy data]# mkdir -p /oldboy/oldboy

[root@oldboy data]# cd /oldboy/oldboy

[root@oldboy oldboy]# pwd

/oldboy/oldboy

4. 【命令】：ls

【功能說明】：

list directory contents #列出目標目錄中所有的子目錄和文件

【語法格式】：

ls [OPTION]... [FILE]...

【選項參數】：

參數	說明	簡解
-a, --all	do not ignore entries starting with.	列出目錄下的所有文件
-A, --almost-all	do not list implied.and ..	同-a，但不列出“.”(表示當前目錄)和“..”(表示當前目錄的父目錄)
-b, --escape	print octal escapes for nongraphic characters	把文件名中不可輸出的字符用反斜杠加字符編號的形式列出
-B, --ignore-backups	do not list implied entries ending with ~	不輸出以“~”結尾的備份文件
-c	sort by ctime	配合-lt；根據ctime排序及顯示ctime(文件狀態最后更改的時間)配合-l：顯示ctime但根據名稱排序否則：根據ctime排序
-C	list entries by clumns	每欄由上至下列出項目
-d, --directory	list directory entries instead of contentsm,and do not dereference symbolic links	將目錄象文件一樣顯示，而不是顯示其下的文件
-D, --dired	generate output designed for Emacs’ dired mode	產生適合Emacs的dired模式使用的結果
-f	do not sort,enable -aU,disable -ls --color	對輸出的文件不進行排序，-aU選項生效，-1st選項失效
-F --classify	append indicator(one of */=>@\|)to entries	在每個文件名后附上一個字符以說明該文件的類型，“*”表示可執行的普通文件；“/”表示目錄；“@”表示符號鏈接；“\|”表示FIFOs；“=”表示套接字(sockets)
-g	like -l,but do not list owner	類似-l，但不列出所有者
-h, --human-readable	with -l,print sizes in human readable format	以容易理解的格式列出文件大小
-H, --dereference-command-line	follow symbolic links listed on the command line	使用命令列中的符號鏈接指示的真正目的地
-i, --inode	print the index number of each file	打印出每個文件的inode號
-I,--ignore=PATTERN	do not list implied entries matching shell PATTERN	不打印出任何符合shell萬用字符<樣式>的項目
-k	like --block-size=1K	以k字節的形式表示文件的大小
-l	use a long listing format	除了文件名之外，還將文件的權限、所有者、文件大小等信息詳細列出來
-L,--dereference	when showing file information for a symbolic link,show information for the file the link references rather than for the link itself	當顯示符號鏈接的文件信息時，顯示符號鏈接所指示的對象而並非符號鏈接本身的信息。
-m	fill width with a comma separated list of entries	所有項目以逗號分隔，並填滿整行行寬
-n, --numeric-uid-gid	like -l,but list numeric user and group IDs	用數字的UID，GID代替名稱
-N, --literal	print raw entry names	不限制文件長度
-o	like -l,but do not list group information	類似-l，顯示文件的除組信息外的詳細信息
-p, --indicator-style=slash	append / indicator to directories	對目錄添加“/”符號
-q, --hide-control-chars	print ? instead of non graphic characters	用？號代替不可輸出的字符
-Q, --quote-name	enclose entry names in double quotes	把輸出的文件名用雙引號括起來
-r, --reverse	reverse order while sorting	依相反次序排列
-R, --recursive	list subdirectories recursively	同時列出所有子目錄層
-s, --size	print the allocated size of each file,in blocks	以塊大小為單位列出所有文件的大小
-S	sort by file size	根據文件大小排序
-t	sort by modification time	以文件修改時間排序
-T, --tabsize=COLS	assume tab stops at each COLS instead of 8
-u	with -lt: sort by, and show, access time with -l:show access time and sort by name otherwise: sort by access time	配合-lt:顯示訪問時間而且依訪問時間排序配合-l：顯示訪問時間但根據名稱排序其他：根據訪問時間排序
-U	do not sort; list entries in directory order	不進行排序；依文件系統原有的次序列出項目
-v	natural sort of (version) numbers within text	根據版本進行排序
-w, --width=COLS	assume screen width instead of current value	自行指定屏幕寬度而不使用目前的數值
-x	list entries by lines instead of by columns	逐行列出項目而不是逐欄列出
-X	sort alphabetically by entry extension	根據擴展名排序
-1	list one file per line	每行只列出一個文件

【示例】：

1、基本用法：查看目錄內容

[root@oldboy ~]# ls

anaconda-ks.cfg data install.log install.log.syslog log1.txt log2.txt test.txt

2、基本用法：查看目錄全部內容（包含隱藏文件）

[root@oldboy ~]# ls -la

total 88

dr-xr-x---. 3 root root 4096 Mar 7 18:16 .

dr-xr-xr-x. 24 root root 4096 Mar 9 17:00 ..

-rw-------. 1 root root 1079 Mar 3 23:14 anaconda-ks.cfg

-rw-------. 1 root root 5003 Mar 9 04:13 .bash_history

-rw-r--r--. 1 root root 18 May 20 2009 .bash_logout

-rw-r--r--. 1 root root 176 May 20 2009 .bash_profile

-rw-r--r--. 1 root root 176 Sep 23 2004 .bashrc

-rw-r--r--. 1 root root 100 Sep 23 2004 .cshrc

drwxr-xr-x. 3 root root 4096 Mar 9 01:47 data

-rw-r--r--. 1 root root 22179 Mar 3 23:14 install.log

-rw-r--r--. 1 root root 5890 Mar 3 23:13 install.log.syslog

-rw-r--r--. 1 root root 18 Mar 7 18:13 log1.txt

-rw-r--r--. 1 root root 44 Mar 7 17:53 log2.txt

-rw-r--r--. 1 root root 129 Dec 4 2004 .tcshrc

-rw-r--r--. 1 root root 0 Mar 7 18:27 test.txt

3、基本用法：查看目錄（使用長模式）

[root@oldboy ~]# ls -l

total 52

-rw-------. 1 root root 1079 Mar 3 23:14 anaconda-ks.cfg

drwxr-xr-x. 3 root root 4096 Mar 9 01:47 data

-rw-r--r--. 1 root root 22179 Mar 3 23:14 install.log

-rw-r--r--. 1 root root 5890 Mar 3 23:13 install.log.syslog

-rw-r--r--. 1 root root 18 Mar 7 18:13 log1.txt

-rw-r--r--. 1 root root 44 Mar 7 17:53 log2.txt

-rw-r--r--. 1 root root 0 Mar 7 18:27 test.txt

5. 【命令】：pwd

【功能說明】：

print name of current/working directory ＃打印當前目錄路徑

【語法格式】：

pwd [OPTION]

【選項參數】：

參數	說明	簡解
-L, --logical	use PWD from environment,even if it contains symlinks	當目錄為鏈接路徑時，顯示鏈接路徑
-P, --physical	avoid all symlinks	顯示實際物理路徑，而非使用鏈接

【示例】：

1、基本用法：顯示當前目錄所在路徑

[root@oldboy ~]# pwd

/root

[root@oldboy ~]#

2、顯示當前目錄的物理路徑

[root@oldboy ~]# cd /etc/init.d

[root@oldboy init.d]# pwd -P

/etc/rc.d/init.d

3、顯示當前目錄的鏈接路徑

[root@oldboy ~]# cd /etc/init.d

[root@oldboy init.d]# pwd -L

/etc/init.d

6. 【命令】：touch

【功能說明】：

change file timestamps ＃創建文件或改變文件的時間戳

【語法格式】：

pwd [OPTION]... FILE...

【選項參數】：

參數	說明	簡解
-a	change only the access time	只更改存取時間
-c, --no-create	do not create any files	不新建任何文檔
-d, --date=STRING	parse STRING and use it instead of current time	使用指定的日期時間，而非現在的時間
-f	(ignored)	忽略
-h, --no-dereference	affect each symbolic link instead of any referenced file (useful only on systems that can change the timestamps of a symlink)	會影響符號鏈接本身，而非符號鏈接所指示的目的地
-m	change only the modification time	只更改變動時間
-r, --reference=FILE	use this file’s times instead of current time	把指定文檔或目錄的日期時間，統統設成和參考文檔或目錄的日期時間相同
-t STAMP	use [[CC]YY]MMDDhhmm[.ss] instead of current time	使用指定格式的日期時間，而非當前時間
--time=WORD	change the specified time: WORD is access, atime, or use: equivalent to -a WORD is modify or mtime: equivalent to -m	使用WORD指定的時間：access、atime、use都等於-a選項的效果，而modify、mtime等於-m選項的效果

【示例】：

1、基本用法：創建新文件

[root@oldboy data]# touch log2012.log log2013.log

[root@oldboy data]# ll

total 0

-rw-r--r--. 1 root root 0 Mar 9 17:48 log2012.log

-rw-r--r--. 1 root root 0 Mar 9 17:48 log2013.log

2、不創建不存在的文件

[root@oldboy data]# touch -c log2014.log

[root@oldboy data]# ll

total 0

-rw-r--r--. 1 root root 0 Mar 9 17:48 log2012.log

-rw-r--r--. 1 root root 0 Mar 9 17:48 log2013.log

3、更新log2012.log的時間和log.log時間戳相同

[root@oldboy data]# touch log.log

[root@oldboy data]# ll

total 0

-rw-r--r--. 1 root root 0 Mar 9 2016 log2012.log

-rw-r--r--. 1 root root 0 Mar 9 2016 log2013.log

-rw-r--r--. 1 root root 0 May 23 00:00 log.log

[root@oldboy data]# touch -r log.log log2012.log

[root@oldboy data]# ll

total 0

-rw-r--r--. 1 root root 0 May 23 00:00 log2012.log

-rw-r--r--. 1 root root 0 Mar 9 2016 log2013.log

-rw-r--r--. 1 root root 0 May 23 00:00 log.log

4、設定文件時間戳

[root@oldboy data]# touch -t 201211142234.50 log2016.log

[root@oldboy data]# ll

total 0

-rw-r--r--. 1 root root 0 Nov 14 2012 log2016.log

【說明】：

-t time 使用指定的時間值 time 作為指定文件相應時間戳記的新值．此處的 time規定為如下形式的十進制數:

[[CC]YY]MMDDhhmm[.SS]

這里，CC為年數中的前兩位，即”世紀數”；YY為年數的后兩位，即某世紀中的年數．如果不給出CC的值，則touch 將把年數CCYY限定在1969--2068之內．MM為月數，DD為天將把年數CCYY限定在1969--2068之內．MM為月數，DD為天數，hh 為小時數(幾點)，mm為分鍾數，SS為秒數．此處秒的設定范圍是0--61，這樣可以處理閏秒．這些數字組成的時間是環境變量TZ指定的時區中的一個時間．由於系統的限制，早於1970年1月1日的時間是錯誤的。

7. 【命令】：echo

【功能說明】：

display a line of text ＃打印輸出

【語法格式】：

echo [SHORT-OPTION]... [STRING]...

echo LONG-OPTION

【選項參數】：

參數	說明	簡解
-n	do not output the trailing newline	不要在最后自動換行
-e	enable interpretation of backslash escapes	若字符串中出現以下字符，則特別加以處理，而不會將它當成一般文字輸出 \a 發出警告聲； \b 刪除前一個字符； \c 最后不加上換行符號； \f 換行但光標仍舊停留在原來的位置； \n 換行且光標移至行首； \r 光標移至行首，但不換行； \t 插入tab； \v 與\f相同； \\ 插入\字符； \nnn 插入nnn（八進制）所代表的ASCII字符；
-E	disable interpretation of backslash escapes (default)	不解釋轉意字符

【示例】：

1、基本用法：打印內容

[root@oldboy data]# echo "I am studying linux."

I am studying linux.

2、打印變量內容

[root@oldboy data]# echo $PATH

/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

8. 【命令】：xargs

【功能說明】：

build and execute command lines from standard input ＃從標准輸入獲取內容創建和執行命令

【語法格式】：

xargs [-0prtx] [-E eof-str] [-e[eof-str]] [--eof[=eof-str]] [--null] [-d delimiter]

[--delimiter delimiter] [-I replace-str] [-i[replace-str]] [--replace[=replace-str]]

[-l[max-lines]] [-L max-lines] [--max-lines[=max-lines]] [-n max-args] [--max-args=max-

args] [-s max-chars] [--max-chars=max-chars] [-P max-procs] [--max-procs=max-procs]

[--interactive] [--verbose] [--exit] [--no-run-if-empty] [--arg-file=file]

[--show-limits] [--version] [--help] [command [initial-arguments]]

【選項參數】：

參數	說明	簡解

【示例】：

1、基本用法：與find配合使用，刪除/data目錄下所有.txt文件

[root@oldboy ~]# find /data -type f -name "*.txt"|xargs rm -f

[root@oldboy ~]# cd /data

[root@oldboy data]# ll

total 0

9. 【命令】：mv

【功能說明】：

move (rename) files ＃移動或重命名文件

【語法格式】：

mv [OPTION]... [-T] SOURCE DEST

mv [OPTION]... SOURCE... DIRECTORY

mv [OPTION]... -t DIRECTORY SOURCE...

【選項參數】：

參數	說明	簡解
--backup[=CONTROL]	make a backup of each existing destination file	備份模式：若需覆蓋文件，則覆蓋前先行備份
-b	like --backup but does not accept an argument	若需覆蓋文件，則覆蓋前先行備份。
-f, --force	do not prompt before overwriting	force 強制的意思，如果目標文件已經存在，不會詢問而直接覆蓋
-i, --interactive	prompt before overwrite	若目標文件 (destination) 已經存在時，就會詢問是否覆蓋
-n, --no-clobber	do not overwrite an existing file
-S, --suffix=SUFFIX	override the usual backup suffix	為備份文件指定后綴，而不使用默認的后綴；
-t, --target-directory=DIRECTORY	move all SOURCE arguments into DIRECTORY	指定mv的目標目錄，該選項適用於移動多個源文件到一個目錄的情況，此時目標目錄在前，源文件在后
-T, --no-target-directory	treat DEST as a normal file
-u, --update	move only when the SOURCE file is newer than the destination file or when the destination file is missing	若目標文件已經存在，且 source 比較新，才會更新(update)
-v, --verbose	explain what is being done	顯示程序執行過程

【示例】：

1、基本用法：移動文件

[root@oldboy ~]# mv ett.txt /root/data

[root@oldboy ~]# cd data

[root@oldboy data]# ll

total 4

-rw-r--r--. 1 root root 292 Mar 9 13:28 ett.txt

2、基本用法：移動目錄

[root@oldboy ~]# mv /data /root

[root@oldboy ~]# ll

total 56

-rw-------. 1 root root 1079 Mar 3 23:14 anaconda-ks.cfg

drwxr-xr-x. 2 root root 4096 Mar 9 13:56 data

-rw-r--r--. 1 root root 22179 Mar 3 23:14 install.log

3、更改文件名

[root@oldboy data]# ll

total 4

-rw-r--r--. 1 root root 292 Mar 9 13:28 ett.txt

[root@oldboy data]# mv ett.txt oldboy.txt

[root@oldboy data]# ll

total 4

-rw-r--r--. 1 root root 292 Mar 9 13:28 oldboy.txt

4、多個文件移動到同一個目錄

[root@localhost test3]# mv -t /opt/soft/test/test4/ log1.txt log2.txt log3.txt

[root@localhost test3]# cd ..

[root@localhost test]# cd test4/

[root@localhost test4]# ll

總計 12

-rw-r--r-- 1 root root 8 10-28 06:15 log1.txt

-rw-r--r-- 1 root root 12 10-28 06:15 log2.txt

-rw-r--r-- 1 root root 13 10-28 06:16 log3.txt

10. 【命令】：rm

【功能說明】：

remove files or directories ＃移除文件或目錄

【語法格式】：

rm [OPTION]... FILE...

【選項參數】：

參數	說明	簡解
-f, --force	ignore nonexistent files,never prompt	忽略不存在的文件，從不給出提示
-i	prompt before every removal	進行交互式刪除
-I	prompt once before removing more than three files, or when removing recursively. Less intrusive than -i, while still giving protection against most mistakes
-r, -R, --recursive	remove directories and their contents recursively	指示rm將參數中列出的全部目錄和子目錄均遞歸地刪除
-v, --verbose	explain what is being done	顯示命令執行過程

【示例】：

1、基本用法：刪除文件

[root@oldboy ~]# rm log1.txt

rm: remove regular file `log1.txt'? y

[root@oldboy ~]# ll

total 52

-rw-------. 1 root root 1079 Mar 3 23:14 anaconda-ks.cfg

drwxr-xr-x. 2 root root 4096 Mar 9 13:56 data

-rw-r--r--. 1 root root 22179 Mar 3 23:14 install.log

-rw-r--r--. 1 root root 5890 Mar 3 23:13 install.log.syslog

-rw-r--r--. 1 root root 44 Mar 7 17:53 log2.txt

-rw-r--r--. 1 root root 18 Mar 9 13:19 oldboy.txt

2、基本用法：刪除目錄

[root@oldboy data]# rm -r a

rm: descend into directory `a'? y

rm: descend into directory `a/b'? y

rm: remove regular empty file `a/b/oldboy.txt'? y

rm: remove directory `a/b/c'? y

rm: remove directory `a/b'? y

rm: remove regular empty file `a/oldboy.txt'? y

rm: remove directory `a'? y

11. 【命令】：find

【功能說明】：

search for files in a directory hierarchy ＃查找文檔

【語法格式】：

find [-H] [-L] [-P] [-D debugopts] [-Olevel] [path...] [expression]

【選項參數】：

參數或選項	說明	簡解
-atime n	File was last accessed n*24 hours ago. When find figures out how many 24-hour periods ago the file was last accessed, any fractional part is ignored, so to match -atime +1, a file has to have been accessed at least two days ago.	根據最后一次的訪問時間查找文件
-ctime n	File’s status was last changed n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file status change times.	根據最后一次的改變時間查找文件
-mtime n	File’s data was last modified n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file modification times.	根據最后一次的修改時間查找文件
-type c	File is of type c: b block (buffered) special c character (unbuffered) special d directory p named pipe (FIFO) f regular file l symbolic link; this is never true if the -L option or the -follow option is in effect, unless the symbolic link is broken. If you want to search for symbolic links when -L is in effect, use -xtype. s socket D door (Solaris)	查找某一類型的文件 b 塊設備文件 d 目錄 c 字符設備文件 p 管道文件 l 符號鏈接文件 f 普通文件 s socket文件
-name pattern	Base of file name (the path with the leading directories removed) matches shell pattern pattern. The metacharacters (‘*’, ‘?’, and ‘[]’) match a ‘.’ at the start of the base name (this is a change in findutils-4.2.2; see section STAN-DARDS CONFORMANCE below). To ignore a directory and the files under it, use -prune; see an example in the description of -path. Braces are not recognised as being special, despite the fact that some shells including Bash imbue braces with a special meaning in shell patterns. The filename matching is performed with the use of the fnmatch(3) library function. Don’t forget to enclose the pattern in quotes in order to protect it from expansion by the shell.	按文件名查找文件
-perm mode	File’s permission bits are exactly mode (octal or symbolic). Since an exact match is required, if you want to use this form for symbolic modes, you may have to specify a rather complex mode string. For example ‘-perm g=w’ will only match files which have mode 0020 (that is, ones for which group write permission is the only permission set). It is more likely that you will want to use the ‘/’ or ‘-’ forms, for example ‘-perm -g=w’, which matches any file with group write permis- sion. See the EXAMPLES section for some illustrative examples.	按照文件權限來查找文件
-size n[cwbkMG]	File uses n units of space. The following suffixes can be used: ‘b’ for 512-byte blocks (this is the default if no suffix is used) ‘c’ for bytes ‘w’ for two-byte words ‘k’ for Kilobytes (units of 1024 bytes) ‘M’ for Megabytes (units of 1048576 bytes) ‘G’ for Gigabytes (units of 1073741824 bytes)	按大小查找

【示例】：

1、基本用法：按文件名查找文件

[root@oldboy ~]# find /root/data -name "*.txt"

/root/data/oldboy.txt

2、基本用法：按文件類型查找文件

[root@oldboy ~]# find /root/data -type f

/root/data/oldboy.txt

3、查找文件名稱不為oldboy.txt的所有文件

[root@oldboy ~]# ll

total 52

-rw-------. 1 root root 1079 Mar 3 23:14 anaconda-ks.cfg

drwxr-xr-x. 2 root root 4096 Mar 9 15:09 data

-rw-r--r--. 1 root root 22179 Mar 3 23:14 install.log

-rw-r--r--. 1 root root 5890 Mar 3 23:13 install.log.syslog

-rw-r--r--. 1 root root 44 Mar 7 17:53 log2.txt

-rw-r--r--. 1 root root 18 Mar 9 13:19 oldboy.txt

[root@oldboy ~]# find /root ! -name "oldboy.txt"

/root

/root/.bash_history

/root/.bashrc

/root/.bash_logout

/root/.bash_profile

/root/data

/root/install.log

/root/log2.txt

/root/.lesshst

/root/.cshrc

/root/anaconda-ks.cfg

/root/install.log.syslog

/root/.tcshrc

4、利用find查找刪除擴展名為txt的所有文件

[root@oldboy data]# ll

total 4

-rw-r--r--. 1 root root 0 Mar 9 16:13 1.txt

-rw-r--r--. 1 root root 0 Mar 9 16:13 2.txt

-rw-r--r--. 1 root root 0 Mar 9 16:13 3.txt

-rw-r--r--. 1 root root 292 Mar 9 13:28 oldboy.txt

[root@oldboy data]# find /root/data -type f -name "*.txt"|xargs rm -f

[root@oldboy data]# ll

total 0

【說明】：

1、按修改時間查找文件，+7表示距今天7天以前，7表示距今天整7天，-7表示最近7天

2、-o表示或者的意思，-a表示並且的意思，！表示取反

12. 【命令】：grep

【功能說明】：

print lines matching a pattern ＃用於過濾、搜索特定字符

【語法格式】：

grep [OPTIONS] PATTERN [FILE...]

grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

【選項參數】：

參數	說明	簡解
-a, --text	Process a binary file as if it were text; this is equivalent to the --binary-files=text option.	不要忽略二進制的數據
-A NUM , --after-context=NUM	Print NUM lines of trailing context after matching lines. Places a line containing a group separator (described under --group-separator) between contiguous groups of matches. With the -o or --only-matching option, this has no effect and a warning is given.	除了顯示符合范本樣式的那一列之外，並顯示該行之后的內容
-b, --byte-offset	Print the 0-based byte offset within the input file before each line of output. If -o (--only-matching) is specified, print the offset of the matching part itself.	在顯示符合樣式的那一行之前，標示出該行第一個字符的編號
-B NUM, --before-context=NUM	Print NUM lines of leading context before matching lines. Places a line containing a group separator (described under --group-separator) between contiguous groups of matches. With the -o or --only-matching option, this has no effect and a warning is given.	除了顯示符合樣式的那一行之外，並顯示該行之前的內容
-c, --count	Suppress normal output; instead print a count of matching lines for each input file. With the -v, --invert-match option (see below), count non-matching lines. (-c is specified by POSIX.)	計算符合樣式的列數
-C NUM, -NUM, --context=NUM	Print NUM lines of output context. Places a line containing a group separator (described under --group-separator) between contiguous groups of matches. With the -o or --only-matching option, this has no effect and a warning is given.	除了顯示符合樣式的那一行之外，並顯示該行之前后各n行內容
-d ACTION, --directories=ACTION	If an input file is a directory, use ACTION to process it. By default, ACTION is read, i.e., read directories just as if they were ordinary files. If ACTION is skip, silently skip directories. If ACTION is recurse, read all files under each directory, recursively, following symbolic links only if they are on the command line. This is equivalent to the -r option.	當指定要查找的是目錄而非文件時，必須使用這項參數，否則grep指令將回報信息並停止動作。
-e PATTERN, --regexp=PATTERN	Use PATTERN as the pattern. This can be used to specify multiple search patterns, or to protect a pattern beginning with a hyphen (-). (-e is specified by POSIX.)	使用正則表達式
-E, --extended-regexp	Interpret PATTERN as an extended regular expression (ERE, see below). (-E is specified by POSIX.)	使用拓展的正則表達式
-f FILE, --file=FILE	Obtain patterns from FILE, one per line. The empty file contains zero patterns, and therefore matches nothing. (-f is specified by POSIX.)	指定規則文件，其內容含有一個或多個規則樣式，讓grep查找符合規則條件的文件內容，格式為每行一個規則樣式。
-h, --no-filename	Suppress the prefixing of file names on output. This is the default when there is only one file (or only standard input) to search.	在顯示符合樣式的那一行之前，不標示該行所屬的文件名稱。
-H, --with-filename	Print the file name for each match. This is the default when there is more than one file to search.	在顯示符合樣式的那一行之前，表示該行所屬的文件名稱。
-i, --ignore-case	Ignore case distinctions in both the PATTERN and the input files. (-i is specified by POSIX.)	忽略字符大小寫的差別。
-l, --files-with-matches	Suppress normal output; instead print the name of each input file from which output would normally have been printed. The scanning will stop on the first match. (-l is specified by POSIX.)	列出文件內容符合指定的樣式的文件名稱。
-L, --files-without-match	Suppress normal output; instead print the name of each input file from which no output would normally have been printed. The scanning will stop on the first match.	列出文件內容不符合指定的樣式的文件名稱。
-n, --line-number	Prefix each line of output with the 1-based line number within its input file. (-n is specified by POSIX.)	在顯示符合樣式的那一行之前，標示出該行的列數編號。
-q, --quiet, --silent	Quiet; do not write anything to standard output. Exit immediately with zero status if any match is found, even if an error was detected. Also see the -s or --no-messages option. (-q is specified by POSIX.)	不顯示任何信息。
-r, --recursive	Read all files under each directory, recursively, following symbolic links only if they are on the command line. This is equivalent to the -d recurse option.	如果文件參數是目錄，該選項將遞歸搜索該目錄下的所有子目錄和文件。同-R
-s, --no-messages	Suppress error messages about nonexistent or unreadable files. Portability note: unlike GNU grep, 7th Edition Unix grep did not conform to POSIX, because it lacked -q and its -s option behaved like GNU grep’s -q option. USG-style grep also lacked -q but its -s option behaved like GNU grep. Portable shell scripts should avoid both -q and -s and should redirect standard and error output to /dev/null instead. (-s is specified by POSIX.)	不顯示錯誤信息。
-v, --invert-match	Invert the sense of matching, to select non-matching lines. (-v is specified by POSIX.)	顯示不包含匹配文本的所有行。
-V, --version	Print the version number of grep to the standard output stream. This version number should be included in all bug reports (see below).	顯示版本信息。
-w, --word-regexp	Select only those lines containing matches that form whole words. The test is that the matching substring must either be at the beginning of the line, or preceded by a non-word constituent character. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Word- constituent characters are letters, digits, and the underscore.	只顯示完整單詞的匹配
-x, --line-regexp	Select only those matches that exactly match the whole line. (-x is specified by POSIX.)	只顯示完整行的匹配

【示例】：

1、基本用法：顯示文件中包含字符串的行

[root@oldboy ~]# cat oldboy.txt

test

liyao

oldboy

[root@oldboy ~]# grep "oldboy" oldboy.txt

oldboy

[root@oldboy ~]#

2、基本用法：顯示文件中不包含字符串的行

[root@oldboy ~]# grep -v "oldboy" oldboy.txt

test

liyao

3、除了顯示匹配的一行外，並顯示該行之后的n行

[root@oldboy ~]# grep 20 -A 10 test.txt

【說明】：

grep的正則表達式:

^ #錨定行的開始如：'^grep'匹配所有以grep開頭的行。

$ #錨定行的結束如：'grep$'匹配所有以grep結尾的行。

. #匹配一個非換行符的字符如：'gr.p'匹配gr后接一個任意字符，然后是p。

* #匹配零個或多個先前字符如：'*grep'匹配所有一個或多個空格后緊跟grep的行。

.* #一起用代表任意字符。

[] #匹配一個指定范圍內的字符，如'[Gg]rep'匹配Grep和grep。

[^] #匹配一個不在指定范圍內的字符，如：'[^A-FH-Z]rep'匹配不包含A-R和T-Z的一個字母開頭，緊跟rep的行。

$..$ #標記匹配字符，如'$love$'，love被標記為1。

\< #錨定單詞的開始，如:'\<grep'匹配包含以grep開頭的單詞的行。

\> #錨定單詞的結束，如'grep\>'匹配包含以grep結尾的單詞的行。

x\{m\} #重復字符x，m次，如：'0\{5\}'匹配包含5個o的行。

x\{m,\} #重復字符x,至少m次，如：'o\{5,\}'匹配至少有5個o的行。

x\{m,n\} #重復字符x，至少m次，不多於n次，如：'o\{5,10\}'匹配5--10個o的行。

\w #匹配文字和數字字符，也就是[A-Za-z0-9]，如：'G\w*p'匹配以G后跟零個或多個文字或數字字符，然后是p。

\W #\w的反置形式，匹配一個或多個非單詞字符，如點號句號等。

\b #單詞鎖定符，如: '\bgrep\b'只匹配grep。

POSIX字符:

為了在不同國家的字符編碼中保持一至，POSIX(The Portable Operating System Interface)增加了特殊的字符類，如[:alnum:]是[A-Za-z0-9]的另一個寫法。要把它們放到[]號內才能成為正則表達式，如[A- Za-z0-9]或[[:alnum:]]。在linux下的grep除fgrep外，都支持POSIX的字符類。

[:alnum:] #文字數字字符

[:alpha:] #文字字符

[:digit:] #數字字符

[:graph:] #非空字符（非空格、控制字符）

[:lower:] #小寫字符

[:cntrl:] #控制字符

[:print:] #非空字符（包括空格）

[:punct:] #標點符號

[:space:] #所有空白字符（新行，空格，制表符）

[:upper:] #大寫字符

[:xdigit:] #十六進制數字（0-9，a-f，A-F）

13. 【命令】：head

【功能說明】：

output the first part of files ＃打印文件的前幾行

【語法格式】：

head [OPTION]... [FILE]...

【選項參數】：

參數	說明	簡解
-c, --bytes=[-]K	print the first K bytes of each file; with the leading ‘-’,print all but the last K bytes of each file	按前K字節打印文件
-n, --lines=[-]K	print the first K lines instead of the first 10; with the leading ‘-’, print all but the last K lines of each file	按前K行打印文件
-q, --quiet, --silent	never print headers giving file names	隱藏文件名
-v, --verbose	always print headers giving file names	顯示文件名

【示例】：

1、基本用法：打印文件前幾行

[root@oldboy ~]# head -n 13 test.txt

2、打印文件前K個字節

[root@oldboy ~]# head -c 20 test.txt

10[root@oldboy ~]#

3、顯示文件名

[root@oldboy ~]# head -v test.txt

==> test.txt <==

14. 【命令】：cp

【功能說明】：

copy files and directories ＃復制文件或目錄

【語法格式】：

cp [OPTION]... [-T] SOURCE DEST

cp [OPTION]... SOURCE... DIRECTORY

cp [OPTION]... -t DIRECTORY SOURCE...

【選項參數】：

參數	說明	簡解
-a, --archive	same as -dR --preserve=all	保持源文件的原有結構和屬性，與選項“-dpR”相同
--backup[=CONTROL]	make a backup of each existing destination file	做一個已存在文件的備份
-b	like --backup but does not accept an argument	覆蓋已存在的目標文件前將目標文件備份
--copy-contents	copy contents of special files when recursive
-d	same as --no-dereference --preserve=links	如果復制的源文件是符號鏈接，僅復制符號鏈接本身，而且保留符號鏈接所指向的目標文件或目錄
-f, --force	if an existing destination file cannot be opened, remove it and try again (redundant if the -n option is used)	強制覆蓋已經存在的目標文件，不提示用戶確認
-i, --interactive	prompt before overwrite (overrides a previous -n option)	在覆蓋已存在的目標文件前提示用戶進行確認
-H	follow command-line symbolic links in SOURCE
-l, --link	link files instead of copying	為源文件創建硬鏈接
-L, --dereference	always follow symbolic links in SOURCE
-n, --no-clobber	do not overwrite an existing file (overrides a previous -i option)
-P, --no-dereference	never follow symbolic links in SOURCE
-p	same as --preserve=mode,ownership,timestamps	復制文件時保持源文件的所有者、權限信息以及時間屬性
--preserve[=ATTR_LIST]	preserve the specified attributes (default: mode,owner-ship,timestamps), if possible additional attributes: context, links, xattr, all
-c	same as --preserve=context
--no-preserve=ATTR_LIST	don’t preserve the specified attributes
--parents	use full source file name under DIRECTORY
-R, -r, --recursive	copy directories recursively	對目錄進行復制操作，采用遞歸的操作方式
--reflink[=WHEN]	control clone/CoW copies. See below.
--remove-destination	remove each existing destination file before attempting to open it (contrast with --force)
--sparse=WHEN	control creation of sparse files. See below.
--strip-trailing-slashes	remove any trailing slashes from each SOURCE argument
-s, --symbolic-link	make symbolic links instead of copying	為源文件創建符號鏈接
-S, --suffix=SUFFIX	override the usual backup suffix	在備份文件時，用指定的后綴“SUFFIX”代替文件名的默認后綴
-t, --target-directory=DIRECTORY	copy all SOURCE arguments into DIRECTORY
-T, --no-target-directory	treat DEST as a normal file
-u, --update	copy only when the SOURCE file is newer than the destination file or when the destination file is missing	當目標文件不存在或者源文件比目標文件新時才進行復制操作
-v, --verbose	explain what is being done	詳細顯示指令執行的操作
-x, --one-file-system	stay on this file system	復制的文件或目錄存放的文件系統，必須與cp指令執行時所處的文件系統相同，否則不復制，亦不處理位於其他分區的文件
-Z, --context=CONTEXT	set security context of copy to CONTEXT

【示例】：

1、基本用法：復制文件到指定位置

[root@oldboy ~]# cp test.txt data

[root@oldboy ~]# cat data/test.txt

2、基本用法：復制目錄到指定位置

[root@oldboy ~]# cp -r /root/data /tmp

[root@oldboy ~]# cd /tmp/data

[root@oldboy data]#

3、復制時保持文件屬性

[root@oldboy ~]# ll

total 56

-rw-------. 1 root root 1079 Mar 3 23:14 anaconda-ks.cfg

drwxr-xr-x. 7 root root 4096 Mar 13 16:25 data

-rw-r--r--. 1 root root 22179 Mar 3 23:14 install.log

-rw-r--r--. 1 root root 5890 Mar 3 23:13 install.log.syslog

-rw-r--r--. 1 root root 44 Mar 7 17:53 log2.txt

-rw-r--r--. 1 root root 18 Mar 9 13:19 oldboy.txt

-rw-r--r--. 1 root root 292 Mar 13 15:13 test.txt

[root@oldboy ~]# cp -p test.txt /tmp

[root@oldboy ~]# ll /tmp

total 108

drwxr-xr-x 7 root root 4096 Mar 13 16:28 data

-rw-r--r-- 1 root root 292 Mar 13 15:13 test.txt

-rw-------. 1 root root 0 Mar 3 23:09 yum.log

-rw-------. 1 root root 100203 Mar 4 00:39 yum_save_tx-2016-03-04-00-39i_5ZVm.yumtx

15. 【命令】：tail

【功能說明】：

output the last part of files ＃打印文件末尾幾行

【語法格式】：

tail [OPTION]... [FILE]...

【選項參數】：

參數	說明	簡解
-c, --bytes=K	output the last K bytes; alternatively, use -c +K to output bytes starting with the Kth of each file	輸出文件尾部的N個字節內容
-f, --follow[={name\|descriptor}]	output appended data as the file grows; -f, --follow, and --follow=descriptor are equivalent	顯示文件最新追加的內容
-F	same as --follow=name --retry	與選項“--follow=name”和“--retry”連用時的功能相同
-n, --lines=K	output the last K lines, instead of the last 10; or use -n +K to output lines starting with the Kth	輸出文件尾部K行內容
--max-unchanged-stats=N	with --follow=name, reopen a FILE which has not changed size after N (default 5) iterations to see if it has been unlinked or renamed (this is the usual case of rotated log files). With inotify, this option is rarely useful.	參看texinfo文檔(默認為5)
--pid=PID	with -f, terminate after process ID, PID dies	與-f合用,表示在進程ID,PID死掉之后結束
-q, --quiet, --silent	never output headers giving file names	不顯示文件名
--retry	keep trying to open a file even when it is or becomes inacces-sible; useful when following by name, i.e., with --follow=name	即使文件不可訪問或者文件稍后變得不可訪問，都始終嘗試打開文件
-s, --sleep-interval=N	with -f, sleep for approximately N seconds (default 1.0) between iterations. With inotify and --pid=P, check process P at least once every N seconds.	與“-f”連用，指定監視文件變化時間所間隔的秒數
-v, --verbose	always output headers giving file names	總在開頭顯示文件名

【示例】：

1、基本用法：顯示文件末尾的n行

[root@oldboy ~]# tail -8 test.txt

100

2、在開頭顯示文件名

[root@oldboy ~]# tail -v -n 8 test.txt

==> test.txt <==

100

16. 【命令】：alias

【功能說明】：

Define or display aliases. ＃顯示或設置別名

【語法格式】：

alias [-p] [name[=value] ... ]

【選項參數】：

參數	說明	簡解
-p	Print all defined aliases in a reusable format	打印已經設置的命令別名

【示例】：

1、基本用法：打印已經設置的別名（-p可以省略）

[root@oldboy ~]# alias -p

alias cp='cp -i'

alias l.='ls -d .* --color=auto'

alias ll='ls -l --color=auto'

alias ls='ls --color=auto'

alias mv='mv -i'

alias rm='rm -i'

alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

2、基本用法：設置新別名

[root@oldboy ~]# alias rm='echo "Do not use rm!"'

[root@oldboy ~]# rm -f test.txt

Do not use rm! -f test.txt

[root@oldboy ~]# alias

alias cp='cp -i'

alias l.='ls -d .* --color=auto'

alias ll='ls -l --color=auto'

alias ls='ls --color=auto'

alias mv='mv -i'

alias rm='echo "Do not use rm!"'

alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

17. 【命令】：unalias

【功能說明】：

Remove each NAME from the list of defined aliases. ＃取消別名

【語法格式】：

unalias [-a] name [name ...]

【選項參數】：

參數	說明	簡解
-a	remove all alias definitions.	取消所有別名

【示例】：

1、基本用法：取消別名

[root@oldboy ~]# alias

alias cp='cp -i'

alias l.='ls -d .* --color=auto'

alias ll='ls -l --color=auto'

alias ls='ls --color=auto'

alias mv='mv -i'

alias rm='echo "Do not use rm!"'

alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

[root@oldboy ~]# unalias rm

[root@oldboy ~]# alias

alias cp='cp -i'

alias l.='ls -d .* --color=auto'

alias ll='ls -l --color=auto'

alias ls='ls --color=auto'

alias mv='mv -i'

alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

2、取消所有別名

[root@oldboy ~]# alias

alias cp='cp -i'

alias l.='ls -d .* --color=auto'

alias ll='ls -l --color=auto'

alias ls='ls --color=auto'

alias mv='mv -i'

alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

[root@oldboy ~]# unalias -a

[root@oldboy ~]# alias

[root@oldboy ~]#

18. 【命令】：seq

【功能說明】：

print a sequence of numbers ＃生成數字序列

【語法格式】：

seq [OPTION]... LAST

seq [OPTION]... FIRST LAST

seq [OPTION]... FIRST INCREMENT LAST

【選項參數】：

參數	說明	簡解
-f, --format=FORMAT	use printf style floating-point FORMAT	格式化輸出
-s, --separator=STRING	use STRING to separate numbers (default: \n)	指定分隔符，默認是換行符
-w, --equal-width	equalize width by padding with leading zeroes	輸出同寬數列，不足的位數用0補齊

【示例】：

1、基本用法：生成數字序列

[root@oldboy ~]# seq 10

2、格式化輸出

[root@oldboy ~]# seq -f 100%g 10

1001

1002

1003

1004

1005

1006

1007

1008

1009

10010

3、指定分隔符

[root@oldboy ~]# seq -s "..." 10

1...2...3...4...5...6...7...8...9...10

[root@oldboy ~]#

4、輸出同寬數列

[root@oldboy ~]# seq -w 10

19. 【命令】：sed

【功能說明】：

stream editor for filtering and transforming text ＃用於過濾和轉化文本的流編輯器

【語法格式】：

sed [OPTION]... {script-only-if-no-other-script} [input-file]...

【選項參數】：

參數	說明	簡解
-n, --quiet, --silent	suppress automatic printing of pattern space	取消默認輸出，只顯示操作過的那一行
-e script, --expression=script	add the script to the commands to be executed	直接在命令列模式上進行sed的動作編輯
-f script-file, --file=script-file	add the contents of script-file to the commands to be executed	運行腳本內的動作
--follow-symlinks	follow symlinks when processing in place; hard links will still be broken
-i[SUFFIX], --in-place[=SUFFIX]	edit files in place (makes backup if extension supplied). The default operation mode is to break symbolic and hard links.This can be changed with --follow-symlinks and --copy	直接修改讀取的文件內容
-c, --copy	use copy instead of rename when shuffling files in -i mode. While this will avoid breaking links (symbolic or hard), the resulting editing operation is not atomic. This is rarely the desired mode; --follow-symlinks is usually enough, and it is both faster and more secure.
-l N, --line-length=N	specify the desired line-wrap length for the ‘l’ command
--posix	disable all GNU extensions.
-r, --regexp-extended	use extended regular expressions in the script	在腳本中應用拓展的正則表達式
-s, --separate	consider files as separate rather than as a single continuous long stream
-u, --unbuffered	load minimal amounts of data from the input files and flush the output buffers more often

【示例】：

1、基本用法：僅列出 /etc/passwd 文件內的第 5-7 行

[root@oldboy ~]# nl /etc/passwd | sed -n '5,7p'

5 lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

6 sync:x:5:0:sync:/sbin:/bin/sync

7 shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

2、利用sed替換取IP地址

[root@oldboy ~]# ifconfig eth0

eth0 Link encap:Ethernet HWaddr 00:0C:29:9C:9A:32

inet addr:10.0.0.8 Bcast:10.0.0.255 Mask:255.255.255.0

inet6 addr: fe80::20c:29ff:fe9c:9a32/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:641 errors:0 dropped:0 overruns:0 frame:0

TX packets:321 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:56546 (55.2 KiB) TX bytes:40576 (39.6 KiB)

[root@oldboy ~]# /sbin/ifconfig eth0 | grep 'inet addr' | sed 's#^.*addr:##g' | sed 's#Bcast.*$##g'

10.0.0.8

3、直接修改文件內容

[root@oldboy ~]# cat test.txt

[root@oldboy ~]# sed -i 's#5#500#g' test.txt

[root@oldboy ~]# cat test.txt

500

【特別說明】：

動作說明： [n1[,n2]]function

n1, n2 ：不見得會存在，一般代表『選擇進行動作的行數』，舉例來說，如果我的動作是需要在 10 到 20 行之間進行的，則『 10,20[動作行為] 』

function：

a ：新增， a 的后面可以接字串，而這些字串會在新的一行出現(目前的下一行)～

c ：取代， c 的后面可以接字串，這些字串可以取代 n1,n2 之間的行！

d ：刪除，因為是刪除啊，所以 d 后面通常不接任何咚咚；

i ：插入， i 的后面可以接字串，而這些字串會在新的一行出現(目前的上一行)；

p ：打印，亦即將某個選擇的數據印出。通常 p 會與參數 sed -n 一起運行～

s ：取代，可以直接進行取代的工作哩！通常這個 s 的動作可以搭配正則表達式！例如 1,20s#old#new#g 就是啦！

20. 【命令】：man

【功能說明】：

format and display the on-line manual pages ＃查看在線幫助手冊

【語法格式】：

man [-acdDfFhkKtwW] [--path] [-m system] [-p string] [-C config_file]

[-M pathlist] [-P pager] [-B browser] [-H htmlpager] [-S sec-

tion_list] [section] name ...

【選項參數】：

參數	說明	簡解

【示例】：

1、基本用法：查看在線幫助

[root@oldboy ~]# man ls

LS(1) User Commands LS(1)

NAME

ls - list directory contents

SYNOPSIS

ls [OPTION]... [FILE]...

以下省略

21. 【命令】：useradd

【功能說明】：

create a new user or update default new user information #創建新用戶或更新默認新用戶的信息

【語法格式】：

useradd [options] LOGIN

useradd -D

useradd -D [options]

【選項參數】：

參數	說明	簡解
-c, --comment COMMENT	Any text string. It is generally a short description of the login, and is currently used as the field for the user's full name.	加上備注文字
-d, --home HOME_DIR	The new user will be created using HOME_DIR as the value for the user's login directory. The default is to append the LOGIN name to BASE_DIR and use that as the login directory name. The parent directory of HOME_DIR must exist otherwise the home directory cannot be created.	指定用戶登入時的起始目錄
-D, defaults	See below, the subsection "Changing the default values".	變更預設值
-e, --expiredate EXPIRE_DATE	The date on which the user account will be disabled. The date is specified in the format YYYY-MM-DD. If not specified, useradd will use the default expiry date specified by the EXPIRE variable in /etc/default/useradd, or an empty string (no expiry) by default.	指定賬號的有效期限
-f, --inactive INACTIVE	The number of days after a password expires until the account is permanently disabled. A value of 0 disables the account as soon as the password has expired, and a value of -1 disables the feature. If not specified, useradd will use the default inactivity period specified by the INACTIVE variable in /etc/default/useradd, or -1 by default.	指定在密碼過期后多少天即關閉該賬號
-g, --gid GROUP	The group name or number of the user's initial login group. The group name must exist. A group number must refer to an already existing group.	指定用戶所屬的群組
-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]	A list of supplementary groups which the user is also a member of. Each group is separated from the next by a comma, with no intervening whitespace. The groups are subject to the same restrictions as the group given with the -g option. The default is for the user to belong only to the initial group.	指定用戶所屬的附加群組
-m, --create-home	Create the user's home directory if it does not exist. The files and directories contained in the skeleton directory (which can be defined with the -k option) will be copied to the home directory.	自動建立用戶的登入目錄
-M	Do not create the user's home directory, even if the system wide setting from /etc/login.defs (CREATE_HOME) is set to yes.	不要自動建立用戶的登入目錄
-N, --no-user-group	Do not create a group with the same name as the user, but add the user to the group specified by the -g option or by the GROUP variable in /etc/default/useradd.	取消建立以用戶名稱為名的群組
-r, --system	Create a system account.	建立系統賬號
-s, --shell SHELL	The name of the user's login shell. The default is to leave this field blank, which causes the system to select the default login shell specified by the SHELL variable in /etc/default/useradd, or an empty string by default.	指定用戶登入后使用的shell
-u, --uid UID	The numerical value of the user's ID. This value must be unique, unless the -o option is used. The value must be non-negative. The default is to use the smallest ID value greater than or equal to UID_MIN and greater than every other user.	指定用戶ID

【示例】：

1、基本用法：創建新用戶

[root@oldboy ~]# useradd test

[root@oldboy ~]# cat /etc/passwd|tail -1

test:x:501:501::/home/test:/bin/bash

22. 【命令】：passwd

【功能說明】：

update user’s authentication tokens ＃為用戶設置或修改密碼

【語法格式】：

passwd [-k] [-l] [-u [-f]] [-d] [-e] [-n mindays] [-x

maxdays] [-w warndays] [-i inactivedays] [-S] [--stdin]

[username]

【選項參數】：

參數	說明	簡解
-d	This is a quick way to delete a password for an account. It will set the named account password-less. Available to root only.	刪除密碼，僅有系統管理者才能使用
-k	The option -k, is used to indicate that the update should only be for expired authentication tokens (passwords); the user wishes to keep their non-expired tokens as before.	設置只有在密碼過期失效后，方能更新
-l	This option is used to lock the specified account and it is available to root only. The locking is performed by rendering the encrypted password into an invalid string (by prefixing the encrypted string with an !).	鎖住密碼
-S	This will output a short information about the status of the password for a given account.Available to root user only.	列出密碼的相關信息，僅有系統管理者才能使用
-u	This is the reverse of the -l option - it will unlock the account password by removing the !prefix. This option is available to root only. By default passwd will refuse to create a password-less account (it will not unlock an account that has only "!" as a password). The force option -f will override this protection.	解開已上鎖的賬號

【示例】：

1、基本用法：設置用戶密碼

[root@oldboy ~]# passwd oldboy

Changing password for user oldboy.

New password:

BAD PASSWORD: it is too simplistic/systematic

BAD PASSWORD: is too simple

Retype new password:

passwd: all authentication tokens updated successfully.

23. 【命令】：uname

【功能說明】：

print system information ＃打印系統信息

【語法格式】：

uname [OPTION]...

【選項參數】：

參數	說明	簡解
-a, --all	print all information, in the following order, except omit -p and -i if unknown:	顯示全部的信息
-s, --kernel-name	print the kernel name	顯示操作系統類型
-n, --nodename	print the network node hostname	顯示主機名
-r, --kernel-release	print the kernel release	顯示核心版本號
-v, --kernel-version	print the kernel version	顯示操作系統的版本
-m, --machine	print the machine hardware name	顯示機器架構類型
-p, --processor	print the processor type or "unknown"
-i, --hardware-platform	print the hardware platform or "unknown"	顯示硬件平台
-o, --operating-system	print the operating system	顯示操作系統

【示例】：

1、基本用法：顯示全部信息

[root@oldboy ~]# uname -a

Linux oldboy 2.6.32-573.el6.x86_64 #1 SMP Thu Jul 23 15:44:03 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

2、基本用法：顯示主機名

[root@oldboy ~]# uname -n

oldboy

3、顯示核心版本號

[root@oldboy ~]# uname -r

2.6.32-573.el6.x86_64

4、顯示機器架構類型

[root@oldboy ~]# uname -m

x86_64

24. 【命令】：hostname

【功能說明】：

show or set the system’s host name ＃顯示和設置主機名

【語法格式】：

hostname [-v] [-a] [--alias] [-d] [--domain] [-f]

[--fqdn] [-A] [--all-fqdns] [-i] [--ip-address] [-I]

[--all-ip-addresses] [--long] [-s] [--short] [-y] [--yp]

[--nis]

hostname [-v] [-F filename] [--file filename] [hostname]

【選項參數】：

參數	說明	簡解
-v, --verbose	Be verbose and tell what’s going on.	詳細信息模式
-a, --alias	Display the alias name of the host (if used)	顯示主機別名
-d, --domain	Display the name of the DNS domain. Don’t use the command domainname to get the DNS domain name because it will show the NIS domain name and not the DNS domain name. Use dnsdomainname instead.	顯示DNS域名
-f, --fqdn, --long	Display the FQDN (Fully Qualified Domain Name). A FQDN consists of a short host name and the DNS domain name. Unless you are using bind or NIS for host lookups you can change the FQDN and the DNS domain name (which is part of the FQDN) in the /etc/hosts file. See the warnings in section THE FQDN above, and avoid using this option; use hostname --all-fqdns instead	顯示FQDN名稱
-i, --ip-address	Display the IP address(es) of the host. Note that this works only if the host name can be resolved. Avoid using this option; use hostname --all-ip- addresses instead	顯示主機的ip地址
-s, --short	Display the short host name. This is the host name cut at the first dot.	顯示短主機名稱，在第一個點處截斷
-y, --yp, --nis	Display the NIS domain name. If a parameter is given (or --file name ) then root can also set a new NIS domain	顯示NIS域名

【示例】：

1、基本用法：顯示主機名

[root@oldboy ~]# hostname

oldboy

2、基本用法：修改主機名

[root@oldboy ~]# hostname oldgirl

[root@oldboy ~]# hostname

oldgirl

25. 【命令】：runlevel

【功能說明】：

output previous and current runlevel ＃查看系統運行狀態

【語法格式】：

runlevel [OPTION]... [UTMP]

【選項參數】：

參數

說明

簡解

--quiet

Does not output the current and previous run-level, nor does it output unknown in the case of error (but it will exit with an error code).

This may be used to test for the presence of a runlevel entry, or to check for errors reading from the file.

不顯示當前運行狀態

【示例】：

1、基本用法：查看系統運行狀態

[root@oldboy ~]# runlevel

N 3

26. 【命令】：init

【功能說明】：

Upstart process management daemon ＃設置系統運行狀態

【語法格式】：

init [OPTION]...

【選項參數】：

參數	說明	簡解
-v, --verbose	Outputs verbose messages about job state changes and event emissions to the system console or log,useful for debugging boot.	顯示詳細信息
-q, --quiet	reduce output to errors only	只顯示錯誤

【示例】：

1、基本用法：關機

[root@oldboy ~]# init 0

2、基本用法：重啟

[root@oldboy ~]# init 6

27. 【命令】：shutdown

【功能說明】：

bring the system down ＃關機

【語法格式】：

shutdown [OPTION]... TIME [MESSAGE]

【選項參數】：

參數	說明	簡解
-r	Requests that the system be rebooted after it has been brought down	重啟系統
-h	Requests that the system be either halted or pow-ered off after it has been brought down, with the choice as to which left up to the system.	關機
-H	Requests that the system be halted after it has been brought down
-P	Requests that the system be powered off after it has been brought down.
-c	Cancels a running shutdown. TIME is not specified with this option, the first argument is MES-SAGE.	當執行“shutdown -h 11:50”指令時，只要按+鍵就可以中斷關機的指令
-k	Only send out the warning messages and disable logins, do not actually bring the system down	只發送警告信息，不真關機

【示例】：

1、基本用法：立即關機

[root@oldboy ~]# shutdown -h now

2、指定12點關機

[root@oldboy ~]# shutdown -h 12:00

Broadcast message from root@oldboy

(/dev/pts/0) at 11:54 ...

The system is going down for halt in 6 minutes!

28. 【命令】：reboot

【功能說明】：

reboot the system ＃重啟系統

【語法格式】：

reboot [OPTION]...

【選項參數】：

參數	說明	簡解
-f, --force	Does not invoke shutdown(8) and instead performs the actual action you would expect from the name.	強制重新開機
-p, --poweroff	Instructs the halt command to instead behave as poweroff
-w, --wtmp-only	Does not call shutdown(8) or the reboot(2) system call and instead only writes the shutdown record to /var/log/wtmp	僅做測試，並不真正將系統重新開機，只會把重開機的數據寫入/var/log目錄下的wtmp記錄文件。
--verbose	Outputs slightly more verbose messages when rebooting, useful for debugging problems with shutdown.
-n, --no-sync	don't sync before reboot or halt

【示例】：

1、基本用法：重啟系統

[root@oldboy ~]# reboot

29. 【命令】：history

【功能說明】：

Display or manipulate the history list. ＃查看命令歷史

【語法格式】：

history [-c] [-d offset] [n] or history -anrw [filename] or history -ps arg [arg...]

【選項參數】：

參數	說明	簡解
-c	clear the history list by deleting all of the entries	清空當前歷史命令
-d	offset delete the history entry at offset OFFSET
-a	append history lines from this session to the history file	將歷史命令緩沖區中命令寫入歷史命令文件中
-n	read all history lines not already read from the history file
-r	read the history file and append the contents to the history list	將歷史命令文件中的命令讀入當前歷史命令緩沖區
-w	write the current history to the history file and append them to the history list
-p	perform history expansion on each ARG and display the result without storing it in the history list
-s	append the ARGs to the history list as a single entry

【示例】：

1、基本用法：查看命令歷史

[root@oldboy ~]# history

1 cd /usr/local/

2 cd ..

3 pwd

4 cd ../..

5 cd -

6 cd ~

7 cd /

8 ll

9 ls -la

......

30. 【命令】：dmesg

【功能說明】：

print or control the kernel ring buffer ＃查看系統故障信息

【語法格式】：

dmesg [-c] [-r] [-n level] [-s bufsize]

【選項參數】：

參數	說明	簡解
-c	Clear the ring buffer contents after printing.	顯示信息后，清除ring buffer中的內容
-r	Print the raw message buffer, i.e., don’t strip the log level prefixes.
-s bufsize	Use a buffer of size bufsize to query the kernel ring buffer. This is 16392 by default. (The default kernel syslog buffer size was 4096 at first, 8192 since 1.3.54, 16384 since 2.1.113.) If you have set the kernel buffer to be larger than the default then this option can be used to view the entire buffer	設置ring buffer大小，預設置為8196，剛好等於ring buffer的大小
-n level	Set the level at which logging of messages is done to the console. For example, -n 1 prevents all messages, except panic messages, from appear-ing on the console. All levels of messages are still written to /proc/kmsg, so syslogd(8) can still be used to control exactly where kernel messages appear. When the -n option is used,dmesg will not print or clear the kernel ring buffer	設置記錄信息的層級

【示例】：

1、基本用法：查看信息

[root@oldboy ~]# dmesg

Initializing cgroup subsys cpuset

Initializing cgroup subsys cpu

Linux version 2.6.32-573.el6.x86_64 (mockbuild@c6b9.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-16) (GCC) ) #1 SMP Thu Jul 23 15:44:03 UTC 2015

Command line: ro root=UUID=8fc55236-ce36-4cc4-9924-202ed5142065 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet

31. 【命令】：ifup、ifdown

【功能說明】：

ifup - bring a network interface up ＃開啟網卡

ifdown - take a network interface down ＃關閉網卡

【語法格式】：

ifup IFACE [boot]

ifdown IFACE

【選項參數】：

參數	說明	簡解

【示例】：

1、基本用法：關閉、開啟網卡

[root@oldboy ~]# ifdown eth0

[root@oldboy ~]# ifup eth0

Determining if ip address 10.0.0.8 is already in use for device eth0...

32. 【命令】：nl

【功能說明】：

number lines of files ＃顯示文件行號

【語法格式】：

nl [OPTION]... [FILE]...

【選項參數】：

參數	說明	簡解
-b, --body-numbering=STYLE	use STYLE for numbering body lines	指定行號指定的方式，主要有兩種： -b a ：表示不論是否為空行，也同樣列出行號(類似 cat -n)； -b t ：如果有空行，空的那一行不要列出行號(默認值)；
-d, --section-delimiter=CC	use CC for separating logical pages
-f, --footer-numbering=STYLE	use STYLE for numbering footer lines
-h, --header-numbering=STYLE	use STYLE for numbering header lines
-i, --line-increment=NUMBER	line number increment at each line
-l, --join-blank-lines=NUMBER	group of NUMBER empty lines counted as one
-n, --number-format=FORMAT	insert line numbers according to FORMAT	列出行號表示的方法，主要有三種： -n ln ：行號在螢幕的最左方顯示； -n rn ：行號在自己欄位的最右方顯示，且不加 0 ； -n rz ：行號在自己欄位的最右方顯示，且加 0 ；
-p, --no-renumber	do not reset line numbers at logical pages	在邏輯定界符處不重新開始計算
-s, --number-separator=STRING	add STRING after (possible) line number
-v, --starting-line-number=NUMBER	first line number on each logical page
-w, --number-width=NUMBER	use NUMBER columns for line numbers	行號欄位的占用的位數

【示例】：

1、基本用法：顯示行號（默認空行不顯示）

[root@oldboy ~]# nl test.txt

1 10

2 14

3 99

4 8a1

5 69

2、顯示行號（空行也顯示）

[root@oldboy ~]# nl -b a test.txt

1 10

2 14

3 99

7 8a1

8 69

3、讓行號前自動補上0，統一輸出格式

[root@oldboy ~]# nl -b a -n rz test.txt

000001 10

000002 14

000003 99

000004

000005

000006

000007 8a1

000008 69

4、調整統一輸出格式為三位數字

[root@oldboy ~]# nl -b a -n rz -w 3 test.txt

001 10

002 14

003 99

004

005

006

007 8a1

008 69

33. 【命令】：less

【功能說明】：

opposite of more ＃分屏查看文本（可回退）

【語法格式】：

less -?

less --help

less -V

less --version

less [-[+]aBcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]

[-b space] [-h lines] [-j line] [-k keyfile]

[-{oO} logfile] [-p pattern] [-P prompt] [-t tag]

[-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]

[-# shift] [+[+]cmd] [--] [filename]...

【選項參數】：

參數	說明	簡解
-bn	Specifies the amount of buffer space less will use for each file, in units of kilobytes (1024 bytes). By default 64K of buffer space is used for each file (unless the file is a pipe; see the -B option). The -b option specifies instead that n kilobytes of buffer space should be used for each file. If n is -1, buffer space is unlimited; that is, the entire file can be read into memory.	設置緩沖區的大小
-e	Causes less to automatically exit the second time it reaches end-of-file. By default, the only way to exit less is via the "q" command.	當文件顯示結束后，自動離開
-f	Forces non-regular files to be opened. (A non-regular file is a directory or a device special file.) Also suppresses the warning message when a binary file is opened. By default, less will refuse to open non-regular files. Note that some operating systems will not allow directories to be read, even if -f is set	強迫打開特殊文件，例如外圍設備代號、目錄和二進制文件
-g	Normally, less will highlight ALL strings which match the last search command. The -g option changes this behavior to highlight only the particular string which was found by the last search command. This can cause less to run somewhat faster than the default	只標志最后搜索的關鍵詞
-i	Causes searches to ignore case; that is, uppercase and lowercase are considered identical. This option is ignored if any uppercase letters appear in the search pattern; in other words, if a pattern contains uppercase letters, then that search does not ignore case	忽略搜索時的大小寫
-m	Causes less to prompt verbosely (like more), with the percent into the file. By default, less prompts with a colon	顯示類似more命令的百分比
-N	Causes a line number to be displayed at the beginning of each line in the display.	顯示每行的行號
-ofilename	Causes less to copy its input to the named file as it is being viewed. This applies only when the input file is a pipe, not an ordinary file. If the file already exists, less will ask for confirmation before overwriting it	將less 輸出的內容在指定文件中保存起來
-Q	Causes totally "quiet" operation: the terminal bell is never rung.	不使用警告音
-s	Causes consecutive blank lines to be squeezed into a single blank line. This is useful when viewing nroff output	顯示連續空行為一行
-S	Causes lines longer than the screen width to be chopped rather than folded. That is, the portion of a long line that does not fit in the screen width is not shown. The default is to fold long lines; that is, display the remainder on the next line	行過長時間將超出部分舍棄
-xn	Sets tab stops. If only one n is specified, tab stops are set at multiples of n. If multiple values separated by commas are specified, tab stops are set at those positions, and then continue with the same spacing as the last two. For example, -x9,17 will set tabs at positions 9, 17,25, 33, etc. The default for n is 8	將“tab”鍵顯示為規定的數字空格

【示例】：

1、基本用法：查看文件

[root@oldboy ~]# less test.txt

8a1

【特別說明】

1.全屏導航

ctrl + F - 向前移動一屏

ctrl + B - 向后移動一屏

ctrl + D - 向前移動半屏

ctrl + U - 向后移動半屏

2.單行導航

j - 向前移動一行

k - 向后移動一行

3.其它導航

G - 移動到最后一行

g - 移動到第一行

q / ZZ - 退出 less 命令

4.其它有用的命令

v - 使用配置的編輯器編輯當前文件

h - 顯示 less 的幫助文檔

&pattern - 僅顯示匹配模式的行，而不是整個文件

5.標記導航

當使用 less 查看大文件時，可以在任何一個位置作標記，可以通過命令導航到標有特定標記的文本位置：

ma - 使用 a 標記文本的當前位置

'a - 導航到標記 a 處

34. 【命令】：more

【功能說明】：

file perusal filter for crt viewing ＃分屏查看文件（不可回退）

【語法格式】：

more [-dlfpcsu] [-num] [+/pattern] [+linenum] [file ...]

【選項參數】：

參數	說明	簡解
+num	Start at line number num	從笫n行開始顯示
-num	This option specifies an integer which is the screen size (in lines)	定義屏幕大小為n行
+/pattern	The +/ option specifies a string that will be searched for before each file is displayed	在每個檔案顯示前搜尋該字串（pattern），然后從該字串前兩行之后開始顯示
-c	Do not scroll. Instead, paint each screen from the top, clearing the remainder of each line as it is displayed.	從頂部清屏，然后顯示
-d	more will prompt the user with the message "[Press space to continue, ’q’ to quit.]" and will display"[Press ’h’ for instructions.]" instead of ringing the bell when an illegal key is pressed	提示“Press space to continue，’q’ to quit（按空格鍵繼續，按q鍵退出）”，禁用響鈴功能
-l	more usually treats ^L (form feed) as a special character, and will pause after any line that contains a form feed. The -l option will prevent this behavior.	忽略Ctrl+l（換頁）字符
-p	Do not scroll. Instead, clear the whole screen and then display the text	通過清除窗口而不是滾屏來對文件進行換頁，與-c選項相似
-s	Squeeze multiple blank lines into one.	把連續的多個空行顯示為一行
-u	Suppress underlining	把文件內容中的下畫線去掉

【示例】：

1、基本用法：查看文件

[root@oldboy ~]# more test.txt

8a1

【特別說明】

Enter 向下n行，需要定義。默認為1行

Ctrl+F 向下滾動一屏

空格鍵向下滾動一屏

Ctrl+B 返回上一屏

= 輸出當前行的行號

：f 輸出文件名和當前行的行號

V 調用vi編輯器

!命令調用Shell，並執行命令

q 退出more

35. 【命令】：wc

【功能說明】：

print newline, word, and byte counts for each file ＃打印行數、字數

【語法格式】：

wc [OPTION]... [FILE]...

wc [OPTION]... --files0-from=F

【選項參數】：

參數	說明	簡解
-c, --bytes	print the byte counts	打印字節數
-m, --chars	print the character counts	打印字符數
-l, --lines	print the newline counts	打印行數
--files0-from=F	read input from the files specified by NUL-terminated names in file F; If F is - then read names from standard input
-L, --max-line-length	print the length of the longest line	打印最長行的長度
-w, --words	print the word counts	打印單詞數

【示例】：

1、基本用法：打印行數、單詞數、字節數及文件名

[root@oldboy ~]# wc test.txt

9 6 22 test.txt

2、只打印統計數字不打印文件名

[root@oldboy ~]# cat test.txt|wc -l

36. 【命令】：chkconfig

【功能說明】：

updates and queries runlevel information for system services ＃管理開機自啟動程序

【語法格式】：

chkconfig [--list] [--type type][name]

chkconfig --add name

chkconfig --del name

chkconfig --override name

chkconfig [--level levels] [--type type] name<on|off|reset|resetpriorities>

chkconfig [--level levels] [--type type] name

【選項參數】：

參數	說明	簡解
--level levels	Specifies the run levels an operation should pertain to. It is given as a string of numbers from 0 to 6. For example, --level 35 specifies run- levels 3 and 5	指定系統服務要在哪一個執行等級中開啟或關畢
--add name	This option adds a new service for management by chkconfig. When a new service is added, chkconfig ensures that the service has either a start or a kill entry in every runlevel. If any run-level is missing such an entry, chkconfig creates the appropriate entry as specified by the default values in the init script. Note that default entries in LSB-delimited ’INIT INFO’ sections take precedence over the default runlevels in the initscript; if any Required-Start or Required-Stop entries are present, the start and stop priorities of the script will be adjusted to account for these dependencies	增加所指定的系統服務，讓chkconfig指令得以管理它，並同時在系統啟動的敘述文件內增加相關數據
--del name	The service is removed from chkconfig management,and any symbolic links in /etc/rc[0-6].d which pertain to it are removed.Note that future package installs for this service may run chkconfig --add, which will re-add such links. To disable a service, run chkconfig name off.	刪除所指定的系統服務，不再由chkconfig指令管理，並同時在系統啟動的敘述文件內刪除相關數據
--list name	This option lists all of the services which chkconfig knows about, and whether they are stopped or started in each runlevel. If name is specified, information in only display about service name.	羅列所有服務在各執行等級上的開啟、關閉情況

【示例】：

1、基本用法：查看所有服務在各執行等級上的開啟、關閉情況

[root@oldboy ~]# chkconfig --list

abrt-ccpp 0:off 1:off 2:off 3:off 4:off 5:off 6:off

abrtd 0:off 1:off 2:off 3:off 4:off 5:off 6:off

acpid 0:off 1:off 2:off 3:off 4:off 5:off 6:off

atd 0:off 1:off 2:off 3:off 4:off 5:off 6:off

auditd 0:off 1:off 2:off 3:off 4:off 5:off 6:off

blk-availability 0:off 1:on 2:off 3:off 4:off 5:off6:off

cpuspeed 0:off 1:on 2:off 3:off 4:off 5:off 6:off

crond 0:off 1:off 2:on 3:on 4:on 5:on 6:off

haldaemon 0:off 1:off 2:off 3:off 4:off 5:off 6:off

......

2、基本用法：在指定執行等級上關閉（開啟）一個服務

[root@oldboy ~]# chkconfig --level 2345 atd off

[root@oldboy ~]# chkconfig --list|grep "atd"

atd 0:off 1:off 2:off 3:off 4:off 5:off 6:off

37. 【命令】：tar

【功能說明】：

manual page for tar 1.23 ＃打包命令

【語法格式】：

tar [OPTION...] [FILE]...

【選項參數】：

參數	說明	簡解
-A	append tar files to an archive	新增壓縮文件到已存在的壓縮
-c	create a new archive	建立新的壓縮文件
-d	find differences between archive and file system	記錄文件的差別
-r	append files to the end of an archive	添加文件到已經壓縮的文件結尾
-u	only append files newer than copy in archive	添加改變了和現有的文件到已經存在的壓縮文件
-x	extract files from an archive	從壓縮的文件中提取文件
-t	list the contents of an archive	顯示壓縮文件的內容
-z	filter the archive through gzip	支持gzip解壓文件
-j	filter the archive through bzip2	支持bzip2解壓文件
-v	verbosely list files processed	顯示操作過程
-W	attempt to verify the archive after writing it	確認壓縮文件的正確性
-C	change to directory DIR	切換到指定目錄
-f	use archive file or device ARCHIVE	指定壓縮文件

【示例】：

1、基本用法：打包文件zcvf

[root@oldboy ~]# tar zcvf data.tar.gz ./data

./data/

./data/d.txt

./data/oldboy.txt

./data/dir5/

./data/dir1/

./data/test.txt

./data/c.txt

./data/dir2/

./data/dir3/

./data/dir4/

./data/e.txt

[root@oldboy ~]# ls

anaconda-ks.cfg install.log oldboy test.txt

data install.log.syslog oldboy.tar.gz

data.tar.gz log2.txt oldboy.txt

2、基本用法：解包zxvf

[root@oldboy tmp]# tar zxvf data.tar.gz

./data/

./data/d.txt

./data/oldboy.txt

./data/dir5/

./data/dir1/

./data/test.txt

./data/c.txt

./data/dir2/

./data/dir3/

./data/dir4/

./data/e.txt

[root@oldboy tmp]# ls

data data.tar.gz file1.txt file2.txt oldboy test.txt

3、批量排除打包

[root@oldboy opt]# cat paichu.log
stu05
stu06
stu07
[root@oldboy opt]# tar zcvfX paichuX.tar.gz paichu.log ./test
./test/
./test/stu03
./test/stu01
./test/stu02
./test/stu09
./test/stu08
./test/stu10
./test/stu04
[root@oldboy opt]# tar tf paichuX.tar.gz
./test/
./test/stu03
./test/stu01
./test/stu02
./test/stu09
./test/stu08
./test/stu10
./test/stu04

38. 【命令】：cut

【功能說明】：

remove sections from each line of files ＃

【語法格式】：

cut OPTION... [FILE]...

【選項參數】：

參數	說明	簡解
-b, --bytes=LIST	select only these bytes	以字節為單位進行分割
-c, --characters=LIST	select only these characters	以字符為單位進行分割
-d, --delimiter=DELIM	use DELIM instead of TAB for field delimiter	自定義分隔符，默認為制表符
-f, --fields=LIST	select only these fields; also print any line that contains no delimiter character, unless the -soption is specified	與-d一起使用，指定顯示哪個區域
-n	with -b: don’t split multibyte characters	取消分割多字節字符僅和 -b 標志一起使用。如果字符的最后一個字節落在由 -b 標志的 List 參數指示的范圍之內，該字符將被寫出；否則，該字符將被排除。
--complement	complement the set of selected bytes, characters or fields	補足被選擇的字節、字符或字段
-s, --only-delimited	do not print lines not containing delimiters	不打印不含分隔符的行
--output-delimiter=STRING	use STRING as the output delimiter the default is to use the input delimiter	指定分隔符打印樣式

【示例】：

1、基本用法：以字節為單位取列

[root@oldboy ~]# cat oldboy.txt

inet addr:10.0.0.8 Bcast:10.0.0.255 Mask:255.255.255.0

[root@oldboy ~]# cut -b6-18 oldboy.txt

addr:10.0.0.8

2、基本用法：以字符為單位取列

[root@oldboy ~]# cat oldboy.txt

inet addr:10.0.0.8 Bcast:10.0.0.255 Mask:255.255.255.0

[root@oldboy ~]# cut -c6-18 oldboy.txt

addr:10.0.0.8

3、基本用法：以分隔符為單位取列

[root@oldboy ~]# cat /etc/passwd|head -5

root:x:0:0:root:/root:/bin/bash

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

[root@oldboy ~]# cat /etc/passwd|head -5|cut -d':' -f5

root

bin

daemon

adm

39. 【命令】：tr

【功能說明】：

translate or delete characters ＃轉換或刪除字符

【語法格式】：

tr [OPTION]... SET1 [SET2]

【選項參數】：

參數	說明	簡解
-c, -C, --complement	use the complement of SET1	取代所有不屬於第一字符集的字符
-d, --delete	delete characters in SET1, do not translate	刪除所有屬於第一字符集的字符
-s, --squeeze-repeats	replace each input sequence of a repeated character that is listed in SET1 with a single occurrence of that character	把連續重復的字符以單獨一個字符表示
-t, --truncate-set1	first truncate SET1 to length of SET2	先刪除第一字符集較第二字符集多出的字符

【示例】：

1、基本用法：替換字符

[root@oldboy ~]# echo abcdef|tr 'a-f' 'x-za-c'

xyzabc

2、刪除字符

[root@oldboy ~]# echo abcdef|tr -d 'a-c'

def

3、連續重復的字符以單獨一個字符表示

[root@oldboy ~]# echo aaabbbccc|tr -s 'abc'

abc

[root@oldboy ~]# echo aaabbbccc|tr -s 'a'

abbbccc

40. 【命令】：stat

【功能說明】：

display file or file system status ＃顯示文件和文件系統狀態（查看文件屬性）

【語法格式】：

stat [OPTION]... FILE...

【選項參數】：

參數	說明	簡解
-L, --dereference	follow links	如果是鏈接文件，則獲取原文件信息
-Z, --context	print the SELinux security context	打印SELinux安全上下文信息
-f, --file-system	display file system status instead of file status	顯示文件系統狀態而非文件狀態
-c --format=FORMAT	use the specified FORMAT instead of the default; output a newline after each use of FORMAT	自定義輸出格式，結尾有換行
--printf=FORMAT	like --format, but interpret backslash escapes, and do not output a mandatory trailing newline. If you want a newline, include \n in FORMAT.	自定義輸出格式，結尾無換行符，需手動添加
-t, --terse	print the information in terse form	以簡潔方式輸出信息

【示例】：

1、基本用法：查看文件信息

[root@oldboy ~]# stat test.txt

File: `test.txt'

Size: 22 Blocks: 8 IO Block: 4096 regular file

Device: 803h/2051d Inode: 11628 Links: 1

Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)

Access: 2016-03-19 16:08:55.616298620 +0800

Modify: 2016-03-19 16:08:44.504300222 +0800

Change: 2016-03-19 16:08:44.505300149 +0800

2、利用stat取文件權限屬性

[root@oldboy ~]# stat test.txt

File: `test.txt'

Size: 22 Blocks: 8 IO Block: 4096 regular file

Device: 803h/2051d Inode: 11628 Links: 1

Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)

......

[root@oldboy ~]# stat -c %a test.txt

644

41. 【命令】：file

【功能說明】：

determine file type ＃顯示文件類型

【語法格式】：

file [-bchikLNnprsvz0] [--apple] [--mime-encoding]

[--mime-type] [-e testname] [-F separator] [-f namefile]

[-m magicfiles] file ...

file -C [-m magicfiles]

file [--help]

【選項參數】：

參數	說明	簡解
-b	Do not prepend filenames to output lines (brief mode)	列出文件辨識結果時，不顯示文件名稱。
-c	Cause a checking printout of the parsed form of the magic file. This is usually used in conjunction with the -m flag to debug a new magic file before installing it	詳細顯示指令執行過程，便於排錯或分析程序執行的情形
-f	Read the names of the files to be examined from namefile (one per line) before the argument list.Either namefile or at least one filename argument must be present; to test the standard input, use ‘-’ as a filename argument.	列出文件中文件名的文件類型
-F	Use the specified string as the separator between the filename and the file result returned. Defaults to‘:’.	使用指定分隔符號替換輸出文件名后的默認的“：”分隔符
-i	Causes the file command to output mime type strings rather than the more traditional human readable ones.Thus it may say ‘text/plain; charset=us-ascii’ rather than ‘ASCII text’. In order for this option to work,file changes the way it handles files recognized by the command itself (such as many of the text file types, directories etc), and makes use of an alternative ‘magic’ file. (See the FILES section, below)	輸出mime類型的字符串
-L	option causes symlinks to be followed, as the like-named option in ls(1) (on systems that support symbolic links). This is the default if the environment variable POSIXLY_CORRECT is defined	查看對應軟鏈接對應文件的文件類型
-z	Try to look inside compressed files.	嘗試去解讀壓縮文件的內容

【示例】：

1、基本用法：顯示文件類型

[root@oldboy ~]# file test.txt

test.txt: ASCII text

[root@oldboy ~]# file /data

/data: directory

42. 【命令】：last

【功能說明】：

show listing of last logged in users ＃查看用戶登錄信息

【語法格式】：

last [-R] [-num] [ -n num ] [-adFiowx] [ -f file ] [ -t

YYYYMMDDHHMMSS ] [name...] [tty...]

lastb [-R] [-num] [ -n num ] [ -f file ] [-adFiowx]

[name...] [tty...]

【選項參數】：

參數	說明	簡解
-a	Display the hostname in the last column. Useful in combination with the next flag	將登錄系統的的主機名稱或IP地址，顯示在最后一行
-d	For non-local logins, Linux stores not only the host name of the remote host but its IP number as well.This option translates the IP number back into a hostname	將IP地址轉換成主機名稱
-f	Specifies a file to search other than /var/log/wtmp	指定記錄文件，默認是顯示/var/log目錄下的wtmp文件的記錄，但/var/log目錄下得btmp能顯示的內容更豐富，可以顯示遠程登錄，例如ssh登錄，包括失敗的登錄請求
-i	This option is like -d in that it displays the IP number of the remote host, but it displays the IP number in numbers-and-dots notation.	-i顯示特定ip登錄的情況。跟蹤用 -i顯示特定ip登錄的情況。跟蹤用
-o	Read an old-type wtmp file (written by linux-libc5 applications).
-n	This is a count telling last how many lines to show.	-n <顯示列數>或-<顯示列數> 　設置列出名單的顯示列數
-w	Display full user and domain names in the output
-R	Suppresses the display of the hostname field	不顯示登入系統的主機名稱或IP（省略 hostname 的欄位）
-t	Display the state of logins as of the specified time. This is useful, e.g., to determine easily who was logged in at a particular time -- specify that time with -t and look for "still logged in"	顯示YYYYMMDDHHMMSS之前的信息
-x	Display the system shutdown entries and run level changes.	顯示系統關閉、用戶登錄和退出的歷史

【示例】：

1、基本用法：查看用戶登錄信息

[root@oldboy ~]# last

oldboy pts/0 10.0.0.1 Sun Mar 20 12:15 still logged in

reboot system boot 2.6.32-573.el6.x Sun Mar 20 12:15 - 15:08 (02:53)

oldboy pts/1 10.0.0.1 Sat Mar 19 15:36 - down (06:49)

root tty1 Sat Mar 19 15:35 - down (06:50)

2、顯示最后登錄系統的N條記錄

[root@oldboy ~]# last -n 10

oldboy pts/0 10.0.0.1 Sun Mar 20 12:15 still logged in

reboot system boot 2.6.32-573.el6.x Sun Mar 20 12:15 - 15:25 (03:10)

oldboy pts/1 10.0.0.1 Sat Mar 19 15:36 - down (06:49)

root tty1 Sat Mar 19 15:35 - down (06:50)

oldboy pts/0 10.0.0.1 Sat Mar 19 10:28 - 15:52 (05:24)

reboot system boot 2.6.32-573.el6.x Sat Mar 19 10:28 - 22:25 (11:57)

root tty1 Sat Mar 19 10:27 - down (00:00)

oldboy pts/0 10.0.0.1 Sat Mar 19 10:20 - down (00:07)

oldboy pts/0 10.0.0.1 Sat Mar 19 10:19 - 10:20 (00:00)

reboot system boot 2.6.32-573.el6.x Sat Mar 19 10:19 - 10:27 (00:08)

wtmp begins Thu Mar 3 23:14:45 2016

3、將IP地址轉換成主機名稱

[root@oldboy ~]# last -n 5 -d

oldboy pts/0 localhost Sun Mar 20 12:15 still logged in

reboot system boot 0.0.0.0 Sun Mar 20 12:15 - 15:27 (03:11)

oldboy pts/1 localhost Sat Mar 19 15:36 - down (06:49)

root tty1 0.0.0.0 Sat Mar 19 15:35 - down (06:50)

oldboy pts/0 localhost Sat Mar 19 10:28 - 15:52 (05:24)

4、指定/var/log/btmp文件，查看登錄系統的用戶相關信息

[root@oldboy ~]# last -n 5 -f /var/log/btmp

btmp begins Thu Mar 3 23:14:22 2016

43. 【命令】：lastlog

【功能說明】：

reports the most recent login of all users or of a given user ＃查看最近登錄的用戶信息

【語法格式】：

lastlog [options]

【選項參數】：

參數	說明	簡解
-b, --before DAYS	Print only lastlog records older than DAYS	顯示指定天數前的登錄信息
-h, --help	Display help message and exit.	顯示幫助
-t, --time DAYS	Print the lastlog records more recent than DAYS	顯示指定天數以來的登錄信息
-u, --user LOGIN\|RANGE	Print the lastlog record of the specified user(s)	顯示指定用戶的最近登錄信息

【示例】：

1、基本用法：顯示最近登錄的用戶信息

[root@oldboy ~]# lastlog

Username Port From Latest

root tty1 Sat Mar 19 15:35:02 +0800 2016

bin **Never logged in**

daemon **Never logged in**

adm **Never logged in**

lp **Never logged in**

sync **Never logged in**

shutdown **Never logged in**

halt **Never logged in**

mail **Never logged in**

......

oldboy pts/0 10.0.0.1 Sun Mar 20 12:15:35 +0800 2016

test **Never logged in**

2、顯示某一個用戶最近登錄信息

[root@oldboy ~]# lastlog -u oldboy

Username Port From Latest

oldboy pts/0 10.0.0.1 Sun Mar 20 12:15:35 +0800 2016

44. 【命令】：df

【功能說明】：

report file system disk space usage ＃查看系統磁盤空間的使用情況

【語法格式】：

df [OPTION]... [FILE]...

【選項參數】：

參數	說明	簡解
-a	include dummy file systems	包含全部的文件系統
-B	use SIZE-byte blocks	以指定的區塊大小來顯示區塊數目
-h	print sizes in human readable format (e.g., 1K 234M 2G)	以可讀性較高的方式來顯示信息
-H	likewise, but use powers of 1000 not 1024	與-h相同，但在計算時是以1000Bytes為換算單位而非1024 Bytes
-i	list inode information instead of block usage	顯示inode的信息
-k	like --block-size=1K	指定區塊大小為1024字節
-l	limit listing to local file systems	僅顯示本地的文件系統
--no-sync	do not invoke sync before getting usage info (default)	在取得磁盤使用信息前，不要執行sync指令，此為預設值
-P	use the POSIX output format	使用POSIX的輸出格式
--sync	invoke sync before getting usage info	在取得磁盤使用信息前，先執行sync指令
-t	limit listing to file systems of type TYPE	僅顯示指定文件系統類型的磁盤信息
-T	print file system type	顯示文件系統的類型
-x	limit listing to file systems not of type TYPE	不要顯示指定文件系統類型的磁盤信息

【示例】：

1、基本用法：查看磁盤空間使用情況

[root@oldboy ~]# df

Filesystem 1K-blocks Used Available Use% Mounted on

/dev/sda3 7149156 1494028 5285312 23% /

tmpfs 243320 0 243320 0% /dev/shm

/dev/sda1 194241 40498 143503 23% /boot

[root@oldboy ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 6.9G 1.5G 5.1G 23% /

tmpfs 238M 0 238M 0% /dev/shm

/dev/sda1 190M 40M 141M 23% /boot

2、基本用法：查看inode的消耗情況

[root@oldboy ~]# df -hi

Filesystem Inodes IUsed IFree IUse% Mounted on

/dev/sda3 452K 55K 397K 13% /

tmpfs 60K 1 60K 1% /dev/shm

/dev/sda1 50K 39 50K 1% /boot

[root@oldboy ~]# df -i

Filesystem Inodes IUsed IFree IUse% Mounted on

/dev/sda3 462384 56221 406163 13% /

tmpfs 60830 1 60829 1% /dev/shm

/dev/sda1 51200 39 51161 1% /boot

45. 【命令】：dumpe2fs

【功能說明】：

dump ext2/ext3/ext4 filesystem information ＃查看文件系統內部信息（元數據）

【語法格式】：

dumpe2fs [ -bfhixV ] [ -o superblock=superblock ] [ -o blocksize=block-

size ] device

【選項參數】：

參數	說明	簡解
-b	print the blocks which are reserved as bad in the filesystem	打印文件系統中預留的塊信息
-o superblock=superblock	use the block superblock when examining the filesystem. This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem	指定檢查文件系統時使用的超級塊
-o blocksize=blocksize	use blocks of blocksize bytes when examining the filesystem.This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem	檢查文件系統時使用指定的塊大小
-f	force dumpe2fs to display a filesystem even though it may have some filesystem feature flags which dumpe2fs may not understand(and which can cause some of dumpe2fs’s display to be suspect)
-h	only display the superblock information and not any of the block group descriptor detail information	僅顯示超級塊信息
-i	display the filesystem data from an image file created by e2image, using device as the pathname to the image file	從指定的文件系統映像文件中讀取文件系統信息
-x	print the detailed group information block numbers in hexadecimal format	以16進制格式打印信息塊成員
-V	print the version number of dumpe2fs and exit.

【示例】：

1、基本用法：查看文件系統內部信息

[root@oldboy ~]# dumpe2fs /dev/sda1

dumpe2fs 1.41.12 (17-May-2010)

Filesystem volume name: <none>

Last mounted on: /boot

Filesystem UUID: 3e368f7e-0775-4c00-afba-f8880d916366

Filesystem magic number: 0xEF53

Filesystem revision #: 1 (dynamic)

Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super huge_file uninit_bg dir_nlink extra_isize

Filesystem flags: signed_directory_hash

Default mount options: user_xattr acl

......

Group 0: (Blocks 1-8192) [ITABLE_ZEROED]

Checksum 0x303a, unused inodes 2009

Primary superblock at 1, Group descriptors at 2-2

Reserved GDT blocks at 3-258

Block bitmap at 259 (+258), Inode bitmap at 275 (+274)

Inode table at 291-546 (+290)

3785 free blocks, 2009 free inodes, 6 directories, 2009 unused inodes

Free blocks: 4408-8192

Free inodes: 40-2048

Group 1: (Blocks 8193-16384) [INODE_UNINIT, ITABLE_ZEROED]

......

46. 【命令】：tree

【功能說明】：

list contents of directories in a tree-like format ＃以樹的形式羅列目錄內容

【語法格式】：

tree [-adfghilnopqrstuvxACDFNS] [-L level [-R]] [-H baseHREF] [-T title] [-o

filename] [--nolinks] [-P pattern] [-I pattern] [--inodes] [--device]

[--noreport] [--dirsfirst] [--version] [--help] [--filelimit #] [directory

...]

【選項參數】：

參數	說明	簡解
-a	All files are printed. By default tree does not print hidden files(those beginning with a dot ‘.’). In no event does tree print the file system constructs ‘.’ (current directory) and ‘..’ (previous directory)	顯示所有文件和目錄
-A	Turn on ANSI line graphics hack when printing the indentation lines	使用ASNI繪圖字符顯示樹狀圖而非以ASCII字符組合
-C	Turn colorization on always, using built-in color defaults if the LS_COLORS environment variable is not set. Useful to colorize output to a pipe	在文件和目錄清單加上色彩，便於區分各種類型
-d	List directories only	只羅列目錄
-D	Print the date of the last modification time for the file listed	列出文件或目錄的更改時間
-L	Max display depth of the directory tree	羅列的層次深度
-f	Prints the full path prefix for each file	在每個文件或目錄之前，顯示完整的相對路徑名稱
-F	Append a ‘/’ for directories, a ‘=’ for socket files, a ‘*’ for executable files and a ‘\|’ for FIFO’s, as per ls -F	在執行文件，目錄，Socket，符號連接，管道名稱名稱，各自加上"*","/","=","@","\|"號
-g	Print the group name, or GID # if no group name is available, of the file.	列出文件或目錄的所屬群組名稱，沒有對應的名稱時，則顯示群組識別碼
-i	Makes tree not print the indentation lines, useful when used in conjunction with the -f option	不以階梯狀列出文件或目錄名稱
-I	Do not list those files that match the wild-card pattern	不顯示符合范本樣式的文件或目錄名稱
-l	Follows symbolic links if they point to directories, as if they were directories. Symbolic links that will result in recursion are avoided when detected	如遇到性質為符號連接的目錄，直接列出該連接所指向的原始目錄
-n	Turn colorization off always, over-ridden by the -C option	不在文件和目錄清單加上色彩
-N	Print non-printable characters as is instead of the default caret notation	直接列出文件和目錄名稱，包括控制字符
-p	Print the file type and permissions for each file (as per ls -l)	列出權限標示
-P	List only those files that match the wild-card pattern. Note: you must use the -a option to also consider those files beginning with a dot ‘.’ for matching. Valid wildcard operators are ‘*’ (any zero or more characters), ‘?’ (any single character), ‘[...]’ (any single character listed between brackets (optional - (dash) for character range may be used: ex: [A-Z]), and ‘[^...]’ (any single character not listed in brackets) and ‘\|’ separates alternate patterns	只顯示符合范本樣式的文件或目錄名稱
-q	Print non-printable characters in filenames as question marks instead of the default caret notation	用"?"號取代控制字符，列出文件和目錄名稱
-s	Print the size of each file in bytes along with the name	列出文件或目錄大小
-t	Sort the output by last modification time instead of alphabetically	用文件和目錄的更改時間排序
-u	Print the username, or UID # if no username is available, of the file	列出文件或目錄的擁有者名稱，沒有對應的名稱時，則顯示用戶識別碼
-x	Stay on the current file-system only. Ala find -xdev	將范圍局限在現行的文件系統中，若指定目錄下的某些子目錄，其存放於另一個文件系統上，則將該子目錄予以排除在尋找范圍外

【示例】：

1、基本用法：以樹形羅列目錄

[root@oldboy ~]# tree oldboy

oldboy

├── ext

│ └── oldboy

├── jeacen

├── oldboy

├── test

├── wodi.gz

├── xiaodong

├── xiaofan

├── xingfujie

└── yingsui.gz

2、只羅列目錄

[root@oldboy ~]# tree -d

├── data

│ ├── dir1

│ ├── dir2

│ ├── dir3

│ ├── dir4

│ └── dir5

└── oldboy

├── ext

├── test

├── xiaodong

├── xiaofan

└── xingfujie

3、只羅列目錄，顯示深度為1層

[root@oldboy ~]# tree -Ld 1

├── data

└── oldboy

4、顯示完整的相對路徑

[root@oldboy ~]# tree -f data

data

├── data/c.txt

├── data/dir1

├── data/dir2

├── data/dir3

├── data/dir4

├── data/dir5

├── data/d.txt

├── data/e.txt

├── data/oldboy.txt

└── data/test.txt

5、不以階梯狀形式顯示

[root@oldboy ~]# tree -i data

data

c.txt

dir1

dir2

dir3

dir4

dir5

d.txt

e.txt

oldboy.txt

test.txt

6、為顯示內容添加提示符

[root@oldboy ~]# tree -F oldboy

oldboy

├── ext/

│ └── oldboy

├── jeacen

├── oldboy

├── test/

├── wodi.gz

├── xiaodong/

├── xiaofan/

├── xingfujie/

└── yingsui.gz

47. 【命令】：id

【功能說明】：

print real and effective user and group IDs ＃顯示用戶ID及組ID

【語法格式】：

id [OPTION]... [USERNAME]

【選項參數】：

參數	說明	簡解
-a	ignore, for compatibility with other versions
-Z	print only the security context of the current user
-g	print only the effective group ID	顯示用戶所屬群組的ID
-G	print all group IDs	顯示用戶所有群組的ID
-n	print a name instead of a number, for -ugG	顯示用戶所屬群組的名稱
-r	print the real ID instead of the effective ID, with -ugG	顯示實際ID
-u	print only the effective user ID	顯示用戶ID

【示例】：

1、基本用法：顯示用戶ID及組ID

[oldboy@oldboy ~]$ id oldboy

2、顯示用戶ID

[oldboy@oldboy ~]$ id -u oldboy

500

48. 【命令】：ln

【功能說明】：

make links between files ＃創建鏈接

【語法格式】：

ln [OPTION]... [-T] TARGET LINK_NAME (1st form)

ln [OPTION]... TARGET (2nd form)

ln [OPTION]... TARGET... DIRECTORY (3rd form)

ln [OPTION]... -t DIRECTORY TARGET... (4th form)

【選項參數】：

參數	說明	簡解
-f	remove existing destination files	鏈接時先將與dist同檔案名的檔案刪除
-d	allow the superuser to attempt to hard link directories (note: will probably fail due to system restrictions, even for the superuser)	允許系統管理者硬鏈接自己的目錄
-i	prompt whether to remove destinations	在刪除與dist同名的檔案時先進行詢問
-n	treat destination that is a symlink to a directory as if it were a normal file	在進行軟鏈接時，將dist視為一般的檔案
-s	make symbolic links instead of hard links	創建軟鏈接
-v	print name of each linked file	在鏈接之前顯示其檔案名
-b	like --backup but does not accept an argument	將在鏈接時會被覆寫或刪除的檔案進行備份
-S	override the usual backup suffix	將備份的檔案都加上SUFFIX的字尾

【示例】：

1、基本用法：創建文件硬鏈接

[root@oldboy ~]# ln oldboy.txt oldboy_hard_link

[root@oldboy ~]# ls

anaconda-ks.cfg install.log log2.txt oldboy_hard_link oldboy.txt

data install.log.syslog oldboy oldboy.tar.gz test.txt

2、基本用法：創建文件軟鏈接

[root@oldboy ~]# ln -s oldboy.txt oldboy_soft_link

[root@oldboy ~]# ls

anaconda-ks.cfg install.log log2.txt oldboy_hard_link oldboy.tar.gz test.txt

data install.log.syslog oldboy oldboy_soft_link oldboy.txt

49. 【命令】：du

【功能說明】：

estimate file space usage ＃查看文件和目錄大小

【語法格式】：

du [OPTION]... [FILE]...

du [OPTION]... --files0-from=F

【選項參數】：

參數	說明	簡解
-a	write counts for all files, not just directories	顯示目錄中所有文件大小
-b	equivalent to ‘--apparent-size --block-size=1’	顯示目錄或文件大小時，以byte為單位
-c	produce a grand total	顯示一個大小總和
-k	like --block-size=1K	以KB為單位輸出
-m	like --block-size=1M	以MB為單位輸出
-s	display only a total for each argument	僅顯示總計，只列出最后加總的值
-h	print sizes in human readable format (e.g., 1K 234M 2G)	人類可讀
-x	skip directories on different file systems	以一開始處理時的文件系統為准，若遇上其它不同的文件系統目錄則略過
-L	dereference all symbolic links	顯示選項中所指定符號鏈接的源文件大小
-S	do not include size of subdirectories	顯示個別目錄的大小時，並不含其子目錄的大小
-X	exclude files that match any pattern in FILE
--exclude=PATTERN	exclude files that match PATTERN	略過指定的目錄或文件
-D	dereference only symlinks that are listed on the command line	顯示指定符號鏈接的源文件大小
-H	equivalent to --dereference-args (-D)	與-h參數相同，但是是以1000為換算單位
-l	count sizes many times if hard linked	重復計算硬鏈接的文件

【示例】：

1、基本用法：顯示目錄或文件所占空間

[root@oldboy ~]# du

4 ./oldboy/xiaofan

8 ./oldboy/ext

4 ./oldboy/xingfujie

4 ./oldboy/xiaodong

4 ./oldboy/test

40 ./oldboy

4 ./data/dir5

4 ./data/dir1

4 ./data/dir2

4 ./data/dir3

4 ./data/dir4

28 ./data

172 .

2、顯示指定文件所占空間

[root@oldboy ~]# du oldboy.txt

4 oldboy.txt

3、顯示指定目錄所占空間

[root@oldboy ~]# du oldboy

4 oldboy/xiaofan

8 oldboy/ext

4 oldboy/xingfujie

4 oldboy/xiaodong

4 oldboy/test

40 oldboy

4、以易讀模式顯示

[root@oldboy ~]# du -h

4.0K ./oldboy/xiaofan

8.0K ./oldboy/ext

4.0K ./oldboy/xingfujie

4.0K ./oldboy/xiaodong

4.0K ./oldboy/test

40K ./oldboy

4.0K ./data/dir5

4.0K ./data/dir1

4.0K ./data/dir2

4.0K ./data/dir3

4.0K ./data/dir4

28K ./data

172K .

50. 【命令】：which

【功能說明】：

shows the full path of (shell) commands ＃從PATH變量所在路徑查找二進制命令

【語法格式】：

which [options] [--] programname [...]

【選項參數】：

參數	說明	簡解

【示例】：

1、基本用法：查找命令

[root@oldboy ~]# which cat

/bin/cat

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