sed add line at end of file

If you want to add a a line of text to the end of a file, and want to do the edit in place, use this syntax:

sed -i '$ a\This is some sample text.'  /foo/bar

sed with variables

Here is an example of how to get sed to replace values within files with variables:

for a in {1..12} ; do sed -e s/0/"$a"/g myConfig > myConfig$a ; done;


This is useful if you need to have an iterated set of config files, for instance.

In place editing of files quickly

Use the sed -i option for in place editing of files:

sed -i 's/foo/bar/g' FILENAME

It will replace all occurances of foo with bar within FILENAME

Rename files which match specific criteria

This renames all files within the current working directory from .exe to .exeold. This is useful if you are trying to rename any file extension from one to another.

for file in *.exe ; do mv $file `echo $file | sed 's/\(.*\.\)exe/\1exeold/'` ; done