How can you check if a command can be executable or not in Linux.
Example:
xeyes
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3 Answers
From man bash in the conditional expressions paragraph:
-x file
True if file exists and is executable.
So, you can use:
[ -x /usr/bin/xeyes ] && echo "File is executable" || echo "File is not an executable or does not exist"
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This fails completely when using
-x $(which bogus)instead of-x /usr/bin/bogus. For it,which bogus >/dev/null && echo "available" || echo "unavailable"works just fine for me.Asclepius– Asclepius2020-11-08 21:25:33 +00:00Commented Nov 8, 2020 at 21:25 -
-x $(which bogus)does not work for me either, but adding quotes around the expression as such:-x "$(which bogus)"does.randomuser5767124– randomuser57671242022-08-09 22:45:47 +00:00Commented Aug 9, 2022 at 22:45 -
Gee, both these work -- suppose our command is
needrestart:if [[ -x "$(command -v needrestart)" ]] ; then echo "yes"; else echo "nope"; fior:if [[ -x "$(which needrestart)" ]] ; then echo "yes"; else echo "nope"; fiIt just happens that this command is not available to regular users, only to root, so...scrat.squirrel– scrat.squirrel2024-01-11 15:58:18 +00:00Commented Jan 11, 2024 at 15:58
If you know the location of where the command binary is kept, just do an ls -l. If you don't know the location first find out location using which command
$ which xeyes
/usr/bin/xeyes
If the command has execute permission ( x ) set, then it is executable.
$ ls -l /usr/bin/
-rw-rw-r-- 1 arushirai arushirai 0 May 23 11:58 123
-rwxrwxr-x 1 arushirai arushirai 0 May 23 11:58 xeyes
The -x <filename> actually checks if the file has execute permission set
Explanation:
THe first column of ls -l shows the permission on file.
-rwxrwxr-x
- r is read permission
- w is write permission
- x is execute permission
-rwxrwxr-x
- 1st bit: tells
type of file(-is for regular file ) - Next 3 bits:
ownerpermission (rwx: read, write and execute ) - Next 3 bits:
grouppermission (rwx: read , write and execute ) - Next 3 bits:
otherpermission (r-x: read and execute permission )
For more information on file permissions read: https://wiki.archlinux.org/index.php/File_permissions_and_attributes
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In case your command is symlinked (is a shortcut), you can find the source of the symlink:
readlink -f $(which your-command-here)scrat.squirrel– scrat.squirrel2024-01-11 16:00:10 +00:00Commented Jan 11, 2024 at 16:00
If you don't known a path to the command you can use which to check where it is (of course, if you have it in $PATH). If you know a path to command file use if -x /path/to/command statement.
