Writing an Awk Script

Question

How to write a simple Awk script to parse the output of the ps command

Answer 1

If you want to extract PID (column 1 of ps output) you can do:

ps | awk '{print $1}'

Answer 2

not sure what you are trying to do, but in its simplest case, awk will split on whitespace into strings you can reference via $. here's an example: ps -ef | awk '{print $1 $2 }'

$1 is the first token, $2 is the second, etc.

Answer 3

What @codaddict said, but it's interesting to know also that $0 is useful if you need the whole line.

Answer 4

Try reading ps manual first. (either google 'man ps' or type it in a terminal) You can customize output of ps command and that usually mean you won't need awk to extract data.

Answer 5

Your question wasn't very specific, but here's how you would use a simple Awk one liner to parse for the user name:

ps aux | awk '$1~/pratik/'

And here's how you would find jobs with PIDs greater than 14000

ps aux | awk '$2>14000'

These examples just print the results that satisfy the conditional.

$0 is the entire line string
$1 is the user name when calling ps aux
$2 is the PID
...
and so on...

To do a more complex action, after the conditional, but before the closing tick put statements inside {}. Arithmetic and other statements can be executed this way.

To turn this into a script, make a file ps_username.awk:

#!/bin/awk -f

/jmick/ {
  print
}

and call something like :

ps aux |awk -f ps_username.awk

The awk script needs info to work with so here we're piping the output of ps aux into it.

Edit: As Dennis pointed there was no need for a temporary file in my original command.