The -i switch is usually used for one-liner in-place file edits, combined with the -p switch. So, to substitute 'foo' with 'bar' in a file, from the commandline: 

perl -pi -e's/foo/bar/g' filename

# or, to leave a backup with a .bak extension:

perl -pi.bak -e's/foo/bar/g' filename

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In reply to Re: perl -i by danger
in thread perl -i by malloc

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