Ivorde Unix/Linux/Database/Web/Mail Forum

[debuser]

This article will show only a few example that would be enough for most people:

How to remove multiple white spaces from a string:

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# echo 'some     white            spaces' | sed 's/  *//g'
somewhitespaces


How to replace multiple white spaces from a string:

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# echo 'some     white            spaces' | sed 's/  */\ /g'
some white spaces


Above sed command replaces multiple spaces with a single space. You can adjust it to replace multiple spaces with other characters, like pipe (|):

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# echo 'some     white            spaces' | sed 's/  */\|/g'
some|white|spaces


Special attention needs to be paid to the start and end of the lines:

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# echo '             some     white            spaces ' | sed 's/  */\|/g'
|some|white|spaces|


Above example contains multiple spaces at the beginning and one space at the end of the line. Sed replaced all with a pipe.
All of the above sed regular expressions in the replaced field (/ */) contain two spaces, followed by a ster (*). Omitting this will mess up your script.