The shell determines whether a file or directory exists

Shell Determines whether a file exists1. Shell to determine the file, whether the directory exists or has permissions
2. #!/bin/sh
3.
4. Mypath= "/var/log/httpd/"
5. Myfile= "/var/log/httpd/access.log"
6.
7. # the-x parameter here determines whether the $mypath exists and has executable permissions
8. If [!-X "$myPath"]; Then
9. mkdir "$myPath"
Ten. Fi
One by one .
12. # The-d parameter here determines whether $mypath exists
if [!-D "$myPath"]; Then
mkdir "$myPath"
. Fi
.
17. # Here's the-f parameter to determine if $myfile exists
if [!-F "$myFile"]; Then
touch "$myFile"
. Fi
.
22. # Other parameters also have-n,-n is to determine whether a variable has a value
if [!-n "$myVar"]; Then
echo "$myVar is empty"
Exit 0
. Fi
.
28. # Two variables are judged equal
if ["$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!  transferred from: http://www.cnblogs.com/sunyubo/archive/2011/10/17/2282047.html

The shell determines whether a file or directory exists