SHELL讀取文件的方法

 

1、shell判斷文件,目錄是否存在或者具有權限 

#!/bin/sh 

myPath="/var/log/httpd/" 
myFile="/var /log/httpd/access.log" 

# 這里的-x 參數判斷$myPath是否存在並且是否具有可執行權限 
if [ ! -x "$myPath"]; then 
mkdir "$myPath" 
fi 
 
# 這里的-d 參數判斷$myPath是否存在 
if [ ! -d "$myPath"]; then 
mkdir "$myPath" 
fi 

# 這里的-f參數判斷$myFile是否存在 
if [ ! -f "$myFile" ]; then 
touch "$myFile" 
fi 

# 其他參數還有-n,-n是判斷一個變量是否是否有值 
if [ ! -n "$myVar" ]; then 
echo "$myVar is empty" 
exit 0 
fi 

# 兩個變量判斷是否相等 
if [ "$var1" = "$var2" ]; then 
echo '$var1 eq $var2' 
else 
echo '$var1 not eq $var2' 
fi 

 

-f 和-e的區別 

Conditional Logic on Files 

-a file exists. -b file exists and is a block special file. -c file exists and is a character special file. -d file exists and is a directory. -e file exists (just the same as -a). -f file exists and is a regular file. -g file exists and has its setgid(2) bit set. -G file exists and has the same group ID as this process. -k file exists and has its sticky bit set. -L file exists and is a symbolic link. -n string length is not zero. -o Named option is set on. -O file exists and is owned by the user ID of this process. -p file exists and is a first in, first out (FIFO) special file or named pipe. -r file exists and is readable by the current process. -s file exists and has a size greater than zero. -S file exists and is a socket. -t file descriptor number fildes is open and associated with a terminal device. -u file exists and has its setuid(2) bit set. -w file exists and is writable by the current process. -x file exists and is executable by the current process. -z string length is zero. 是用 -s 還是用 -f 這個區別是很大的！

 

 

2、 SHELL讀取文件的方法

#使用read命令讀取一行數據
while read myline
do
echo "LINE:"$myline
done < datafile.txt

#使用read命令讀取一行數據
cat datafile.txt | while read myline
do 
echo "LINE:"$myline
done

#讀取一行數據，若多行則讀取每一行數據
cat datafile.txt | while myline=$(line)
do 
echo "LINE:"$myline
done

備注：此種方式已驗證沒有問題。

#讀取一行數據
while myline=$(line)
do 
echo "LINE:"$myline
done < datafile.txt

#使用read命令讀取變量數據
cat datafile.txt | while read paraa parab parac
do
echo "PARAA:"$paraa
echo "PARAB:"$parab
echo "PARAC:"$parac
done

#使用read命令讀取變量數據
while read paraa parab parac
do
echo "PARAA:"$paraa
echo "PARAB:"$parab
echo "PARAC:"$parac
done < datafile.txt

 

3、使用

通過對文件的判斷與讀取，可實現讀取一個文件中每行數據，進而實現對每行數據進一步處理。

實例：

1) 獲取某程序所有已打開的pid，將pid打印出來，或關閉此進程。

a.sh文件，批量執行日志文件打印操作

#!/bin/bash
time=$(date +%F-%H-%M)
echo "$time------start--------"

res_dir=/home/weblogic/domains/scmsDomain4500/log
to_dir=/tmp/201601

echo "開始執行命令"
cd $res_dir
pwd
tail -f ManagedServer9802.out>$to_dir/9802_$time.log &
tail -f ManagedServer9803.out>$to_dir/9803_$time.log &
tail -f ManagedServer9804.out>$to_dir/9804_$time.log &

echo "命令執行結束"

 

b.sh文件，批量停止tail -f 的命令

#!/bin/bash

dir="/tmp/201601/"
cd $dir

echo "打印當前tail的進程數"
ps -ef|grep tail|grep -v "grep"|awk -F " " '{print $2}'|wc -l

echo "將tail進程號保存到一個文件中"
ps -ef|grep tail|grep -v "grep"|awk -F " " '{print $2}'>$dir/data.log


echo "打印該文件"
more data.log

echo "開始執行命令"

if [ ! -f "$data.log" ]; then

cat data.log|while myline=$(line)

do

echo $myline
echo “刪除該進程”
kill -9 $myline

done
fi

echo "刪除該文件"
rm -f data.log

echo "命令執行結束"