How do I assign this regex match from an OUTPUT value to a variable using bash?

Question

My current value of $OUTPUT is:

Updating (122 files)

In this case, I want to capture the 122 and assign it to a variable.

I was thinking of using a regex like \d* to capture the number, but I'm unclear on the syntax for working with regular expressions in bash.`

fredtantini · Accepted Answer · 2014-03-21 23:00:46Z

2

I would use sed:

OUTPUT=$(echo $OUTPUT| sed 's/[^0-9]//g')

to delete all non-digit characters for instance.

answered Mar 21, 2014 at 23:00

fredtantini

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Comments

kojiro · Accepted Answer · 2014-03-21 22:45:44Z

2

$ output='Updating (122 files)'
$ output="${output##*(}"
$ output="${output%% *}"
$ echo "$output"
122

You can tweak the pattern if you need more flexible matching.

answered Mar 21, 2014 at 22:45

kojiro

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chepner · Accepted Answer · 2014-03-22 04:27:55Z

2

Using regular expressions,

$ regex="Updating \(([[:digit:]]+) files\)"
$ [[ $OUTPUT =~ $regex ]]
$ echo ${BASH_REMATCH[1]}
122

In this case, there is enough context that you could simplify the regular expression to

regex="Updating \((.*) files\)"

answered Mar 22, 2014 at 4:27

chepner

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