Name
test
Synopsis
testexpression
[expression
]
Also exists as a built-in in most shells.
Evaluates an expression and, if its value is
true
, returns a zero exit status; otherwise,
return a nonzero exit status. In shell scripts, you can use the
alternate form
[
expression
]
.
This command is generally used with conditional constructs in shell
programs.
File testers
The syntax for all of these options is test
option
file. If the
specified file does not exist, the testers return
false
. Otherwise, they test the file as specified
in the option description.
-
-b
Is the file block special?
-
-c
Is the file character special?
-
-d
Is the file a directory?
-
-e
Does the file exist?
-
-f
Is the file a regular file?
-
-g
Does the file have the set-group-ID bit set?
-
-k
Does the file have the sticky bit set?
-
-L,-h
Is the file a symbolic link?
-
-p
Is the file a named pipe?
-
-r
Is the file readable by the current user?
-
-s
Is the file nonempty?
-
-S
Is the file a socket?
-
-t
[file-descriptor
] Is the file associated with file-descriptor (or 1, which is standard output, by default) connected to a terminal?
-
-u
Does the file have the set-user-ID bit set?
-
-w
Is the file writable by the current user?
-
-x
Is the file executable?
-
-O
Is the file owned by the process’s effective user ID?
-
-G
Is the file owned by the process’s effective group ID?
File comparisons
The syntax for file comparisons is test
file1
option
file2. A string by itself, without options,
returns true
if it’s at least one
character long.
-
-nt
Is file1 newer ...
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