Grep a number from a line in ksh - Shell Programming and Scripting

rodluo · #1 (**permalink**) 12-09-2007

In file.name, I have a line that reads

$IDIR/imgen -usemonths -dropcheck -monitor -sizelimit 80000000 -interval 120 -volcal HSI

How can I get the size limit, i.e. 80000000 out and pass it to a variable called SIZE?

Thanks. I tried
echo "grep sizelimit file.name" | sed -n -e 's/^.sizelimit$[0-9]*$ -interval.*$/\1/p'

but it output nothing.

prowla · #2 (**permalink**) 12-09-2007

So close...

Code:

SIZE=`grep sizelimit myfile | sed 's/^.*sizelimit //' | awk '{print $1}'`

should work (NB. It allows for the arguments to be in a different order in the file).
There are other options that involve parsing the line (either in awk or shell), like:

Code:

SIZE=0
grep sizelimit myfile | while read s
do
  set -- $s
  while [ $# -gt 0 ]
  do
    case $1 in
      -sizelimit) SIZE=$2; break;;
      *) shift;;
    esac
  done
done

rodluo · #3 (**permalink**) 12-09-2007

Quote:

Originally Posted by prowla

So close...

Code:

SIZE=`grep sizelimit myfile | sed 's/^.*sizelimit //' | awk '{print $1}'`

should work (NB. It allows for the arguments to be in a different order in the file).
There are other options that involve parsing the line (either in awk or shell), like:

Code:

SIZE=0
grep sizelimit myfile | while read s
do
  set -- $s
  while [ $# -gt 0 ]
  do
    case $1 in
      -sizelimit) SIZE=$2; break;;
      *) shift;;
    esac
  done
done

Thanks a lot prowla!
The first option works fine. Did you mean it works even if "-sizelimit 80000000" is moved somewhere else in the line too?

prowla · #4 (**permalink**) 12-09-2007

Quote:

Originally Posted by rodluo

Thanks a lot prowla!
The first option works fine. Did you mean it works even if "-sizelimit 80000000" is moved somewhere else in the line too?

No probs, and yes - the line can change just so long as -sizelimit is followed by its value.
What it actually does is chops everything from the start of the line up to and including the word sizelimit and the space after, and then takes the first word from the remainder (which is the value of sizelimit).

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