At my current client, I'm often given GUIDs for one reason or another. Often they are not in the format that I need them to be. Sometimes they have the dashes and I need them to be dash-free. Other times, the dashes have been removed and I need them back.
Here's some quick, down and dirty sed commands to swap them back and forth:
To remove the dashes:
$ echo 8EC60070-685F-41DB-C881-EACF9E74E4BD | sed 's/-//g'
8EC60070685F41DBC881EACF9E74E4BD
$
To put them back:
$ echo 8EC60070685F41DBC881EACF9E74E4BD | sed -rn 's/([0-9A-F]{8})([0-9A-F]{4})([0-9A-F]{4})([0-9A-F]{4})([0-9A-F]{12})/\1-\2-\3-\4-\5/p')
8EC60070-685F-41DB-C881-EACF9E74E4BD
$
It goes without saying you can embed this very sed command in a bash script and run it over many rows in a file.