Shell condition Test

File Status Test
-B FileName: Returns True when filename exists and is a block file (returns 0)
-C FileName: Returns True when filename exists and is a character file
-D Pathname: Returns True when pathname exists and is a directory
-E Pathname: Returns True when a file or directory specified by pathname is present
-F FileName: Returns True when filename exists and is a regular file
-G Pathname: Returns True when the file or directory specified by pathname is present and the Sgid bit is set
-H FileName: Returns True when filename exists and is a symbolic link file (or-l filename)
-K Pathname: Returns True when a file or directory specified by pathname exists and the "sticky" bit is set
-P FileName: Returns True when filename exists and is named pipe
-R Pathname: Returns True when a file or directory specified by pathname exists and is readable
-S FileName: Returns True when filename exists and the file size is greater than 0 o'clock
-S FileName: Returns True when filename exists and is a socket
-T FD: Returns True when FD is a file descriptor associated with an end device
-U Pathname: Returns True when the file or directory specified by pathname is present and the SUID bit is set
-W Pathname: Returns True when a file or directory specified by pathname exists and is writable
-X Pathname: Returns True when a file or directory specified by pathname exists and is executable
-O Pathname: Returns True when a user with a valid user ID of the current process exists and is owned by pathname (letter O uppercase)
-G Pathname: Returns True when the user group of a user that is present by pathname and belongs to the current process's valid user ID
File1-nt file2:file1 than File2 new when return True
File1-ot file2:file1 than file2 back true
Example: if [-b/dev/hda]; then echo "yes"; else echo "no"; fi//will print Yes
Test-c/dev/hda; echo $? Will print 1 to indicate that the return value of the test command is 1,/DEV/HDA not a character device
[-W/ETC/PASSWD]; echo $? See if the passwd file is writable for the current user

Test-time logical operator
-a logic with, both sides of the operator are true, the result is true, otherwise false.
-O logic or, the operator is true on either side, the result is true, otherwise false.
! Logical No, the condition is false and the result is true.
Example: [-w Result.txt-a-W Score.txt]; echo $? Test whether two files are writable

Common string tests
-Z String: strings string is a null string (length 0) returns True
-N String: Strings string is a non-empty string when returning true
STR1 = str2: Returns True when string str1 and string str2 are equal
Str1! = str2: Returns True when string str1 and string str2 are not equal
STR1 < str2: sorted by dictionary order, string str1 before string str2
str1 > str2: Sorted in dictionary order, string str1 after string str2
Example: Name= "ZQF"; [$name = "ZQF"];echo $? Printing 0 means the value of the variable name and the string "ZQF" are equal

Common numerical tests
Int1-eq int2: If Int1 equals Int2, returns True
Int1-ne Int2: If int1 is not equal to Int2, returns True
Int1-lt Int2: If Int1 is less than Int2, returns true
Int1-le Int2: Returns True if Int1 is less than or equal to Int2
INT1-GT Int2: If Int1 is greater than Int2, returns true
Int1-ge Int2: Returns True if Int1 is greater than or equal to Int2
Example: x=1; [$x-eq 1]; echo $? Printing 0 means that the value of the variable x equals the number 1
X=a; [$x-eq "1"]//Shell print error message [: A:integer expression expected

Posted from: http://blog.chinaunix.net/u/21352/showart_135230.html]
posted from:http://www.blogjava.net/jasmine214--love/archive/2011/02/09/343963.html

Shell condition Test