From below text in file:
current_build: 22
previous_build: 55
I am only trying to grep number value of current_build.
When run following command
grep -o -E '[0-9]+' textfile
The output is both number like below
22
55
How do i only grep the value 22
With GNU grep:
grep -Po 'current_build: \K.*' file
\K: removes matching part before \K
Output:
22
I would use awk because it is portable in opposite to grep -o which only works with GNU grep:
awk '/current_build/{print $NF}' file
awk splits the input into fields. The default field separator is a sequence of blank chars. NF is the number of fields, $NF is the last field.
Only print lines matching current_build at the start of the line and show the part after the last space:
sed -n 's/current_build:.* //p' file
awk '/current_build/{print $2}' file