I have a file with multiple lines.
Which the second column is the
user_id, but the last seven number are random numbers.
It need to be trimmed off to get the authentic ID.
So what I need is to get the
1st character to the -7 character of the second column of each line.
substr function of awk, it seems can't handle this job directly.
So, how to cut from the 1st character to -7 character in awk?