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.

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 · 676 weeks 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 · 657 weeks 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?

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