Sed only print matched expression

regexsed

How to make sed only print the matched expression?

I want to rewrite strings like "Battery 0: Charging, 44%, charging" to
"Battery: 44%". I tried the following:

sed -n '/\([0-9]*%\)/c Battery: \1'

This doesn't work.

The common "solution" out there is to use search and replace and match the whole line:
sed -n 's/.*\([0-9]*%\).*/Battery: \1/p'
Now the .* are too greedy and the \1 is only the %.

Furthermore I don't want to match more than I need to.

Best Answer

  • Make the regexp a little more specific.

    sed -n 's/.* \([0-9]*%\),.*/Battery: \1/p'

  • Pick a different tool.

    perl -ne '/(\d+%)/ && print "Battery: $1\n";'

    (just for the record, foo && bar is shorthand for if (foo) { bar }.)

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