Extract number from first line of a file in linux

Question

I have a file which has contents like the below

SPEC.2.ATTRID=REVISION&
SPEC.2.VALUE=5&
SPEC.3.ATTRID=NUM&
SPEC.3.VALUE=VS&

I am using the below command to extract only the numbers from the first line. Is this way efficient or you guys think of an alternate way ?

cat ticketspecdata | tr -d " " | tr -s "[:alpha:]" "~" | tr -d "[=.=]" | cut -d "~" -f2

Answer 1

Using grep :

$ grep -om1 '[0-9]\+' file
2

Answer 2

Or

head -n1 file | tr -cd '[:digit:]'

You may also want to read about UUOC:

• http://porkmail.org/era/unix/award.html