I tried to find the solution here but could not; given strings like
ABC3
DFGSS34
CVBB3
how do I extract the integers so I get
3
34
3
??
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4 Answers
Just a simple sed command will do the job:
sed 's/[^0-9]//g' file.txt
OUTPUT
3
34
3
3 Comments
A Sahra
What is the case for fractional number eg: 123.43 ?
anubhava
Since question was extracting integer so this was answer for that. For floating point a different solution is needed.
anubhava
It is not appropriate to answer a new question from comment section. If you post a question then I will surely try to answer.
For a bash-only solution, you can use parameter patter substition:
pax$ xyz=ABC3 ; echo ${xyz//[A-Z]/}
3
pax$ xyz=DFGSS34 ; echo ${xyz//[A-Z]/}
34
pax$ xyz=CVBB3 ; echo ${xyz//[A-Z]/}
3
It's very similar to sed solutions but has the advantage of not having to fork another process. That's probably not important for small jobs but I've had situations where this sort of thing was done to many, many lines of a file and the non-forking is a significant speed boost.
1 Comment
Izzy
This doesn't take into consideration there might be other non-alphanumeric characters in the given string, such as
()[]{}#$!. etc. Shouldn't it better read echo ${xyz//[^0-9]/} instead for extracting "nothing but integers"?How about using tr?
for s in ABC3 DFGSS34 CVBB3 ; do
tr -cd 0-9 <<<"$s"
echo
done
Comments
What about a grep version?
grep -o '[0-9]*' file.txt
3 Comments
Mahdi
grep -o '[0-9][0-9]*' file.txt
bmk
@Mahdi: For this particular use case that's not necessary. But in general you are right.
General Redneck
why not grep -o "[0-9]\+" instead of grep -o '[0-9][0-9]*'