What GNU/Linux command-line tool would I use for performing a search and replace on a file?

Question

What GNU/Linux command-line tool would I use for performing a search and replace on a file?

Can the search text, and replacement, be specified in a regex format?

Answer 1

sed 's/a.*b/xyz/g;' old_file > new_file 

GNU sed (which you probably have) is even more versatile:

sed -r --in-place 's/a(.*)b/x\1y/g;' your_file 

Here is a brief explanation of those options:

-i[SUFFIX], --in-place[=SUFFIX] edit files in place (makes backup if extension supplied)

-r, --regexp-extended use extended regular expressions in the script.

The FreeBSD, NetBSD and OpenBSD versions also supports these options.

If you want to learn more about sed, Cori has suggested this tutorial.

Answer 2

Perl was invented for this:

perl -pi -e 's/foo/bar/g;' *.txt 

Any normal s/// pattern in those single quotes. You can keep a backup with something like this:

perl -pi.bak -e 's/foo/bar/g;' *.txt 

Or pipeline:

cat file.txt | perl -ne 's/foo/bar/g;' | less 

But that's really more sed's job.