CODEWITHSUNDEEP
bash
hesson
hesson

Reputation: 1862

Extract token after particular substring in bash

Suppose I have a string variable in a bash script that contained several lines:

blah blah blah
...
...
an interesting parameter: 12345 some other useless stuff...
...
...

I want to extract 12345 from this string. I have tried to look for ways to use 'an interesting parameter:' as a "delimeter" but I couldn't quite get it to work. Is there a clean way of doing this?

Upvotes: 4

Views: 4300

Answers (6)

Avinash Raj
Avinash Raj

Reputation: 174766

Try this sed command,

sed -n '/interesting parameter/ s/.*parameter: \([0-9]\+\) .*/\1/p' file

For your case it would be,

sed -n '/interesting parameter/ s/.*parameter: \([0-9]\+\) .*/\1/p' <<< "$string"

Upvotes: 3

gniourf_gniourf
gniourf_gniourf

Reputation: 46843

Pure Bash using regex:

$ a='blah blah blah
> ...
> ...
> an interesting parameter: 12345 some other useless stuff...
> ...
> ...'
$ [[ $a =~  "an interesting parameter: "([[:digit:]]+) ]] && echo "${BASH_REMATCH[1]}"
12345

Pure Bash using parameter expansions:

$ t=${a#*an interesting parameter: }
$ echo "$t"
12345 some other useless stuff...
...
...
$ u=${t%% *}
$ echo "$u"
12345

Upvotes: 3

chepner
chepner

Reputation: 531718

bash supports regular expression matching without using external programs.

$ str='
blah blah blah
...
...
an interesting parameter: 12345 some other useless stuff...
...
...'
$ [[ $str =~ an\ interesting\ parameter:\ ([[:digit:]]+) ]]

$ echo ${BASH_REMATCH[1]}
12345

The array BASH_REMATCH contains the full match in element 0 and the captured subgroups (in left-to-right order) in subsequent elements.

Upvotes: 5

lashgar
lashgar

Reputation: 5470

Try this:

cat content | grep "an interesting parameter: " | awk '{print $4}'

Upvotes: 1

hek2mgl
hek2mgl

Reputation: 158080

You can use sed:

sed -n 's/.*an interesting parameter: \([0-9]\+\).*/\1/p' <<< "$string"

Upvotes: 3

Kent
Kent

Reputation: 195169

try this:

grep -Po 'an interesting parameter:\s*\K\S*'

Upvotes: 3

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