checking for existence of a file in perl

usrlocal has asked for the wisdom of the Perl Monks concerning the following question:

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Re: checking for existence of a file in perl by Corion (Patriarch) on Jan 13, 2009 at 20:07 UTC
See -X for the `-f` operator, and see perlvar for `$?` resp. system.	[reply] [d/l] [select]
Re: checking for existence of a file in perl by toolic (Bishop) on Jan 13, 2009 at 20:09 UTC
See file tests in -X: `if (-x file.sh)` [download] For checking return code, see system.	[reply] [d/l]
Re: checking for existence of a file in perl by davido (Cardinal) on Jan 13, 2009 at 22:24 UTC
For your specific needs, checking for the existence of a file may be more work than is needed (to do well), and too unreliable. If it's an executable shell script, does it reside in the account's root directory, in a /bin folder somewhere, or in some other alternate location? If the user moves the executable and then puts a pointer in his path the shell script may remain executable, while disappearing from where your Perl script expects it to be. To put it in simple terms, just because the file doesn't exist where you expect it to doesn't mean it won't execute. And just because it does exist doesn't mean it will execute. Rather than testing for its existence, it might be better to test for success in execution. If the real question is "can I execute the script", just do it, and write some code that handles failure to execute. Dave	[reply]
Re: checking for existence of a file in perl by repellent (Priest) on Jan 13, 2009 at 20:13 UTC
To perform a thorough check (for most cases): `# make sure $path is a plain file (not a dir or other type), is readab +le, and is executable if (-f $path && -r $path && -x $path)` [download]	[reply] [d/l]
Re^2: checking for existence of a file in perl by eff_i_g (Curate) on Jan 13, 2009 at 20:20 UTC
Per the docs, this is better written as: `if (-f $path && -r _ && -x _)` [download]	[reply] [d/l]
Re: checking for existence of a file in perl by setebos (Beadle) on Jan 13, 2009 at 22:57 UTC
cli: perldoc -f -e.	[reply]
Re^2: checking for existence of a file in perl by Anonymous Monk on Feb 02, 2009 at 20:05 UTC
also, how do i check wether the returned value is an integer or non-numeric?	[reply]