simple text substitution.

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

Hi All, I know this is pretty simple, but I can not get this to work. I want to substitute all instances of a word contained within a certain file. I have tried this different method:

#perl -ne 's/text/newtext/g' /path/to/file
[download]

but whe I cat/more the file, nothing has been substituted.
I have also tried this:

#perl -ne 's/text/newtext/g' /path/to/file > /path/to/newfile
[download]

i an trying to edit this instance in several config files, so I would rather edit the file directly (after copying, of course).

Thanks!!

Comment on simple text substitution. Select or Download Code

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Re: simple text substitution. by rev_1318 (Chaplain) on Dec 15, 2004 at 15:19 UTC
You are using the wrong switch. The switch you are looking for is not `-n` but `-p`. If you want the file to be edited in place, use the `-i` switch. As an example: to change all occurances of foo in bar in a file: `perl -pi -e 's/foo/bar/g' file` See perlrun for more on perl command switches. HTH, Paul	[reply] [d/l] [select]
Re: simple text substitution. by gellyfish (Monsignor) on Dec 15, 2004 at 15:13 UTC
`perl -pi -e 's/text/newtext/g' /path/to/file` /J\	[reply] [d/l]
Re: simple text substitution. by sauoq (Abbot) on Dec 15, 2004 at 17:42 UTC
Your question has already been answered but I thought someone should clue you in to how `-i` works and why the suggestion was to use `perl -pi -e` rather than `perl -pie` which seems, at first glance, to be the tastier option(s). The reason the otherwise delectable `-pie` wasn't suggested was because it wouldn't work. The `-i` takes an optional argument. A rather useful argument at that. If given, perl renames the original file by appending the argument as a suffix to the filename, thereby preserving it if you make any mistakes in your one-liner. Trust me. If you use it, you will eventually find this feature useful. If you fail to use it, you will eventually wonder why you didn't. Out of habit, I would write your one-liner as: `perl -pi.bak -e 's/text/newtext/g' /path/to/file` [download] So, anyway, if given `-pie` perl would is forced to... errrr... eat the 'e' as the backup suffix. Sadly though, "e" isn't usually a very useful suffix. -sauoq "My two cents aren't worth a dime.";	[reply] [d/l] [select]