Linux Shell Scripting Cookbook - Third Edition

How it works...

The compression command performs the following tasks:

• Removing the \n and \t characters:

        tr -d '\n\t'  

• Removing extra spaces:

        tr -s ' ' or sed 's/[ ]\+/ /g' 

• Removing comments:

        sed 's:/\*.*\*/::g' 

: is used as a sed delimiter to avoid the need to escape / since we need to use /* and */.

In sed, * is escaped as \*.

 .* matches all the text in between /* and */.

• Removing all the spaces preceding and suffixing the {, }, (, ), ;, :, and , characters:

        sed 's/ \?\([{}();,:]\) \?/\1/g' 

The preceding sed statement works like this:

• / \?\([{}();,:]\) \?/ in the sed code is the match part, and /\1 /g is the replacement part.
• \([{}();,:]\) is used to match any one character in the [ { }( ) ; , : ] set (spaces inserted ...