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

Problem

I just accidently clobbered a file I worked hours to code (luckily I have two backups, one on my computer and another on a web server, and a hard copy).

Question

When creating a file through perl, is there a way to check if a file by that name already exists, and complain if it does exist.

I have an idea, but I am looking for a quick solution. I think I could pack some code in that opens the current directory, and tests the given name against all of the files in the directory.

Is there a quicker fix than me having to kluge that in.

2005-11-06 Retitled by planetscape, as per Monastery guidelines
Original title: 'Safe File Hadling'

Comment on Safe File Handling

Replies are listed 'Best First'.
Re: Safe File Handling by tinita (Parson) on Nov 06, 2005 at 01:14 UTC
see perldoc -f -X, especially `-f/-e/-d` update: perldoc perlfunc is a good start to search for a builtin function in perl.	[reply] [d/l]
Re^2: Safe File Handling by CloneArmyCommander (Friar) on Nov 06, 2005 at 01:21 UTC
Thanks :D!	[reply]
Re: Safe File Handling by gloryhack (Deacon) on Nov 06, 2005 at 01:18 UTC
See perldoc perlopentut, where in addition to many useful nuggets, you'll find this one: `sysopen(FH, $path, O_WRONLY \| O_EXCL \| O_CREAT);` [download]	[reply] [d/l]
Re^2: Safe File Handling by CloneArmyCommander (Friar) on Nov 06, 2005 at 01:22 UTC
Thank you :D!	[reply]
Re: Safe File Handling by EvanCarroll (Chaplain) on Nov 06, 2005 at 02:30 UTC
You might also want to check out the -i flag on perl. While I know you said 'creating a file through perl' it would seem that -i might be worth knowing. `-i[extension] edit <> files in place (makes backup if extension supp +lied)` [download] Evan Carroll www.EvanCarroll.com	[reply] [d/l]
Re: Safe File Handling by vek (Prior) on Nov 06, 2005 at 07:26 UTC
The `-e` filetest will give you what you need. `my $filename = 'somefilename'; if (-e $filename) { print "File $filename already exists.\n"; } else { # create the file here... }` [download] -- vek --	[reply] [d/l] [select]
Re: Safe File Handling by Anonymous Monk on Nov 06, 2005 at 18:36 UTC
once you are set to the right path there are a variety of file tests available, one of which is -e to test if it exists. Usage could look like: die "Don't overwrite a file that already exists\n" if -e $filename; Being new to this myself I had to open up the llama book for reference (its chapter 11, page 155 of the 4th edition) or hidden in chapter 3 of the cammel.	[reply]