extract a string after a pattern

Question

I want to extract the numbers following client_id and id and pair up client_id and id in each line.

For example, for the following lines of log,

User(cli         


        

Answer 1

Here's a awk script that works (I put it on multiple lines and made it a bit more verbose so you can see what's going on):

#!/bin/bash

awk 'BEGIN{FS="[\(\):,]"}
/client_id/ {
cid="no_client_id"
for (i=1; i

Output:

03 204
03 491
03 29
04 209
04 301
05 20

Explanation:

• awk 'BEGIN{FS="[\(\):,]"}: invoke awk, use ( ) : and , as delimiters to separate your fields
• /client_id/ {: Only do the following for the lines that contain client_id:
• for (i=1; i: iterate through the fields on each line one field at a time
• if ($i == "client_id") { cid = $(i+1) }: if the field we are currently on is client_id, then its value is the next field in order.
• else if ($i == "id") { id = $(i+1); print cid OFS id;}: otherwise if the field we are currently on is id, then print the client_id : id pair onto stdout
• input_file_name: supply the name of your input file as first argument to the awk script.