Program Input and Output

The -x file tests

• There are gobs of tests you can perform on either a file name, or on an opened file handle, to get status information about the file.
• For example, if you wanted to determine if a file is writable, you could use the conditional if ( -w $theFile).
• To perform the same test on an opened file handle, you could use the conditional if ( -w FILEHANDLE).
• The tests available, and their actions, are as follows:

Table of -x file test operators and actions

Test Symbol	Operation
-x	File or directory is executable
-o	File or directory is owned by user
-R	File or directory is readable by real user, not effective user (differs from -r for setuid programs)
-W	File or directory is writable by real user, not effective user (differs from -w for setuid programs)
-X	File or directory is executable by real user, not effective user (differs from -x for setuid programs)
-O	File or directory is owned by real user, not effective user (differs from -o for setuid programs)
-e	File or directory exists
-z	File or directory exists and has zero size
-s	File or directory exists and has nonzero size (note: directories are never empty).
-f	Entry is a plain file.
-d	Entry is a directory.
-l	Entry is a symlink.
-S	Entry is a socket.
-p	Entry is a named pipe.
-b	Entry is a block special file (a device like a mountable disk).
-c	Entry is a character special file (a device like an I/O device).
-u	File or directory is setuid
-g	File or directory is setgid
-k	File or directory has the sticky bit set.
-t	The isatty() handle on the file is true.
-T	The file contains "text"
-B	The file contains "binary"
-M	Returns modification age in days
-A	Returns access age in days
-C	Returns inode modification age in days