Shell script code to determine if a file exists _linux shell

Implement code One,

#!/bin/sh # to
determine if a file exists
# link:www.jb51.net
# date:2013/2/28

mypath= '/var/log/httpd/
' myfile= ' Var/log/httpd/access.log "

# Here's the-x parameter to determine if $mypath exists and has executable permissions if
[!-X" $myPath "]; then
 mkdir" $myPath " C10/>fi
# Here the-d parameter determines if $mypath exists if
[!-D "$myPath"]; then
 mkdir "$myPath"
fi

# Here's the-F parameter to judge $ MyFile whether there is
an IF [!-F "$myFile"]; then touch
 "$myFile"
fi
# Other parameters and-n,-n is to determine whether a variable has a value if
[!-N ' $ MyVar "]; Then
 echo "$myVar is empty"
 exit 0
fi

# Two variables to determine whether equality if
["$var 1" = "$var 2"]; then
 Echo ' $var 1 eq $var 2 '
else
 Echo ' $var 1 don't eq $var 2 '
fi

Implementation code Two,

#shellDetermine if the folder exists

#If the folder does not exist, create the folder
if [! -D "/ myfolder"]; then
  mkdir / myfolder
fi

#shellJudge files, Whether the directory exists or has permissions  folder= "/var/www/"
file= "/var/www/log"

#-X parameters to determine if $folder exists and has executable permissions if
[! x "$ Folder "]; Then
 mkdir "$folder"
fi

#-D parameters to determine if $folder exists if
[!-D "$folder"]; then
 mkdir "$folder"
F

the I # f parameter determines whether the $file exists
if [!-F "$file"]; then touch
 "$file"
fi #-

n Determines whether a variable has a value
if [!-N "$var"]; Then
 echo "$var is empty"
 exit 0
Fi

# to determine if two variables are equal
if ["$var 1" = "$var 2"]; then
 Echo ' $var 1 EQ $var 2 '
else
 Echo ' $var 1 don't 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 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-a-a-in-a-a-i-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.

Is the difference between the-s or the-F is very big!