Do a search-and-replace in a file after making a backup

for file in <filename>; do cp $file{,.bak} && sed 's/old/new/g' $file.bak > $file; done
"&&" runs sed if and only if the backup completed and /bin/cp exited cleanly. Works for multiple files; just specify multiple filenames (or glob). Use -v switch for cp to play it safe.

0
By: Cenobite
2009-08-25 16:19:45

2 Alternatives + Submit Alt

What Others Think

Note that cp will return a success even if you copy to /dev/null, so if you for some reason have a symlink file.bak -> /dev/null, the command will silently fail to backup. I don't know how perl behaves.
Mikachu · 473 weeks and 3 days ago
sed already has an option for doing this called -i. Just use -i.bak and it will make a backup copy of the old file.
deltaray · 454 weeks and 4 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

You must be signed in to comment.

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands



Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: