File Test Operators

• A file test operator is a unary operator that takes one argument and tests to see if something is true about it. Return a boolean true or false value. 

    Recall:

1. A boolean false is any of the following: '', "","0",'0', or 0. So the following would be false

   if( 0 or "0" or '0' or '' or "" ) { print "This never happens\n"; }

2. A boolean true is everything else. So the following would be true

   if( 1 and "dog" and " " ) { print "This always happens\n"; 

•   $readable = -r "myfile.txt";

   

Operator	Meaning
-r	File is readable by effective uid/gid
-w	File is writable by effective uid/gid
-x	File is executable by effective uid/gid
-o	File is owned by effective uid
-R	File is readable by real uid/gid
-W	File is writable by real uid/gid
-X	File is executable by real uid/gid
-O	File is owned by real uid
-e	File exists
-z	File has zero size
-s	File non-zero size
-f	File is a plain file
-d	File is a directory
-l	File is a symbolic link
-p	File is a named pipe (FIFO)
-s	File is a socket
-b	File is a block special file
-c	File is a character special file
-t	Filehandle is opened to a tty
-u	File has setuid bit set
-g	File has setgid bit set
-k	File has sticky bit set
-T	File is a text file
-B	File a binary file
-M	Age of file in days since last modification
-A	Age of file in days since last access
-C	Age of file in days since last change