What does if( -f <filename> ) in Perl do?

Question

I came across this line of code:

if( -f <filename> ) { ... } 

-f appears to test whether the filename exists or not, but I am not sure. Googling has not helped so far (it is hard to Google for "-f") and neither have my Perl books.

Can anyone please advise?

Answer 1

See perlfunc.

It lists all the Perl built-in functions, including the "file test" ones:

-X FILEHANDLE -X EXPR -X DIRHANDLE -X 

Where -X is one of the following:

-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 (is empty). -s: File has nonzero size (returns size in bytes).  -f: File is a plain file. -d: File is a directory. -l: File is a symbolic link. -p: File is a named pipe (FIFO), or Filehandle is a pipe. -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 an ASCII text file (heuristic guess). -B: File is a "binary" file (opposite of -T).  -M: Script start time minus file modification time, in days. -A: Same for access time. -C: Same for inode change time (Unix, may differ for other platforms)