Shell determines whether a file or folder exists

#!/bin/sh    mypath= "/var/log/httpd/"  myfile= "/var/log/httpd/access.log"    #这里的-x parameter Judging $ Whether the MyPath exists and has enforceable permissions if  [!-X ' $myPath]; then  mkdir "$myPath"  fi  
#这里的-D parameter to determine if $mypath exists if  [!-D "$myPath"]; then  mkdir "$myPath"  fi    #这里的-F parameter to determine if $myfile exists if  [! -F "$myFile"]; Then  touch "$myFile"  fi    #其他参数还有 The-n,-n is to determine if a variable has a value if  [!-n "$myVar"]; then  echo "$myVar is Empty "  exit 0  fi    #两个变量判断是否相等  If [" $var 1 "=" $var 2 "]; then  echo ' $var 1 eq $var 2 '  else
    Echo ' $var 1 not EQ $var 2 '  fi  

The difference between-F and-E

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 have its setgid (2) bit set.

-G file exists and have the same group ID as this process.

-K file exists and have 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 have 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.

is the difference with-s or with-f this is very big!

Shell determines whether a file or folder exists