Shell condition judgment

1. string Judgments

STR1 = str2	True when two strings have the same content, length
Str1! = str2	True when strings str1 and str2 are unequal
-N str1	True when the length of a string is greater than 0 (string non-null)
-Z str1	True when the length of the string is 0 (empty string)
Str1	True when the string str1 is non-empty

2. Judgment of numbers

Int1-eq Int2	Two numbers equal to True
Int1-ne Int2	Two numbers are true.
INT1-GT Int2	Int1 greater than Int2 is true
Int1-ge Int2	Int1 greater than or equal to Int2 true
Int1-lt Int2	Int1 less than Int2 is true
Int1-le Int2	Int1 less than or equal to Int2 true

3. Judgment of documents

-R File	User-readable as true
-W File	User can write as true
-X File	User can perform a true
-F File	File is true for regular files
-D File	File is directory-True
-C file	File is true for character special files
-B File	File is true for block special files
-S file	File non-0 o'clock is true
-T file	True if the specified device is terminal when the file descriptor (default is 1)

4. complex logic judgment

-A	And
-O	Or
!	Non -

　 　　　　　　　　　　　　
　　　　　　　　

End

[-A file] is true if file exists.
[-B file] True if file exists and is a block special file.
[-C file] True if file exists and is a word special.
[-D file] True if file exists and is a directory.
[-E File] True if file exists.
[-F file] True if file exists and is a normal file.
[-G file] True if file exists and Sgid has been set. [-H file] True if file exists and is a symbolic connection.
[-K file] True if file exists and the sticky bit has been set.
[-P file] If file exists and is a name pipe (f if O) is true.
[-R File] True if file exists and is readable.
[-S file] True if file exists and the size is not 0.
[-T FD] true if the file descriptor FD is open and points to a terminal.
[-u file] True if file exists and suid (set user ID) is set.
[-W file] True if file exists and is writable.
[-X file] True if file exists and is executable.
[-o file] True if file exists and is a valid user ID.
[-G file] True if file exists and is a valid user group.
[-L file] True if file exists and is a symbolic connection.
[-N file] If file exists and has been mod if IED since it is last read is true.
[-S file] True if file exists and is a socket.
[File1-nt FILE2] If FILE1 have been changed more recently than FILE2, or if file1exists and FILE2 does not is true.
[File1-ot FILE2] If FILE1 is older than FILE2, or FILE2 exists and FILE1 does not exist, it is true.
[File1-ef FILE2] True if FILE1 and FILE2 point to the same device and node number.
[-O Optionname] true if the shell option "Optionname" is turned on.
[-Z STRING] "STRING" is true if the length is zero.
[-N STRING] or [string] "string" is true if the length is not 0 non-zero.
[STRING1 = = STRING2] If 2 strings are the same. "=" May is used instead of "= =" for strict POSIX compliance is true.
[STRING1! = STRING2] True if the strings are not equal.
[STRING1 < STRING2] if "STRING1" sorts before "STRING2" lexicographically in the Currentlocale is true.
[STRING1 > STRING2] If "STRING1" sorts after "STRING2" lexicographically in thecurrent locale is true.

Shell condition judgment