linux判斷文件是否存在

#!/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.