Perl: the Markov chain saw | |
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perlfunc:_Xby gods (Initiate) |
on Aug 24, 1999 at 22:43 UTC ( [id://370]=perlfunc: print w/replies, xml ) | Need Help?? |
_XSee the current Perl documentation for _X. Here is our local, out-dated (pre-5.6) version: -X filetest operators -X argument indicates a file test, where X is one of the letters listed below. This unary operator takes one argument, either a filename or a filehandle, and tests the associated file to see if something is true about it. If the argument is omitted, tests $_ , except for -t , which tests
STDIN. Unless otherwise documented, it returns 1 for
TRUE and '' for
FALSE, or the undefined value if the file doesn't
exist. Despite the funny names, precedence is the same as any other named
unary operator, and the argument may be parenthesized like any other unary
operator. The operator may be any of:
-r , -w , -x , -o , -R , -W , -X , -O , -e , -z , -s , -f , -d , -l , -p , -S , -b , -c , -t , -u , -g , -k , -T , -B , -M , -A , -C
-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 has nonzero size (returns 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), 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 a text file. -B File is a binary file (opposite of -T).
-M Age of file in days when script started. -A Same for access time. -C Same for inode change time.
The interpretation of the file permission operators Example:
while (<>) { chop; next unless -f $_; # ignore specials #... }
Note that
The
If any of the file tests (or either the
print "Can do.\n" if -r $a || -w _ || -x _;
stat($filename); print "Readable\n" if -r _; print "Writable\n" if -w _; print "Executable\n" if -x _; print "Setuid\n" if -u _; print "Setgid\n" if -g _; print "Sticky\n" if -k _; print "Text\n" if -T _; print "Binary\n" if -B _; |
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