When working with txt files or with the shell in general it is sometimes necessary to replace certain chars in existing files. In that cases sed can come in handy:
sed -i 's/foo/bar/g' FILENAME
The -i option makes sure that the changes are saved in the new file – in case you are not sure that sed will work as you expect it you should use it without the option but provide an output filename. The s is for search, the foo is the pattern you are searching the file for, bar is the replacement string and the g flag makes sure that all hits on each line are replaced, not just the first one.
If you have to replace special characters like a dot or a comma, they have to be entered with a backslash to make clear that you mean the chars, not some control command:
sed -i 's/./,/g' *txt
Sed should be available on every standard installation of any distribution. At lesat on Fedora it is even required by core system parts like udev.
February 27, 2008 at 8:58
For many file :
find . -name “*.txt” -type f -exec sed -i “s/foo/bar/g” {} \;
February 27, 2008 at 9:16
I’ve grown accustomed to use perl for this kind of thing:
perl -pi -e ‘s/foo/bar/g’ FILENAMES
This modifies files in place and allows for reusing matches, e.g.
perl -pi -e ‘s/G(.*)/K\1/g’
(maybe ( should be escaped like \(, i’m not quite sure)
February 27, 2008 at 10:03
Thx for the comments, I’ll keep them in my mind.
February 27, 2008 at 11:06
I always use something like
sed -i~ ‘s/foo/bar/’g FILENAME
which makes a backup of the file with suffix ~. But you can supply nearly everything as a suffix in -i[SUFFIX].
February 27, 2008 at 11:08
Ahh, dammit. Reusing matches is possible too with sed, just use -r.
November 4, 2008 at 16:54
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