Outputting grep to multiple variables

Question

I what to have bash script to grep output to multiple variables but have no idea how to do that:

command |grep bla > $result1 $result2 etc...

Any ideas?

S

Answer 1

use read shell builtin command

Answer 2

Wouldn't something like this work, too:

for BLAH in `command | grep <stuff>`
do
    echo $BLAH
done

Answer 3

It would help if you gave some examples, but I think you might want something like:

while read line; do 
    ip=$(echo $line | egrep -o '\([0-9.]+\)'); 
    echo $ip; 
done < <(ping google.com)

You could then do multiple lines like the ip=... line. -o to grep means only the part that matched.

But really, something that supports capturing groups with the regex is better than grep I think, I would use perl.

Or, if you want each line in a variable, you probably want an array. For example:

$ while IFS= read -r arr[i++]; do :;done < <(ping google.com | grep 'bytes from')
$ echo ${arr[2]}
64 bytes from yx-in-f100.1e100.net (74.125.45.100): icmp_seq=2 ttl=55 time=63.9 ms

---

If you just want 'multiple assignment', the shell doesn't directly support that as far as I know. So you would:

foo=$(command | grep whatever)
bar="$foo"
baz="$foo"

If you need to do that for more than couple variables, you are probably not approacing the problem correctly, as always, best to state your end goal.

Answer 4

You need to expand on what you're trying to do.

For instance, are you trying to parse random output where you want every line that happens after a line that has the word snoopy in it?

Such a thing could be accomplished by read and case in such a way:

command | grep blah |
while
  read line
do 
  case "$line"
  in
    *snoopy*) 
            read result_after_snoopy ;

            echo "This is where I do something when I find a line with the word snoopy in it and the line that comes after"
            echo "this is what I do with the line with snoopy in it" 
            echo "$line" | cut -f3 -d%
            echo "This is what I do with the line after"
            echo "$result_after_snoopy" | md5sum
        ;;
    *woodstock*) echo "This line had woodstock in it"
        ;;
  esac
done

If you want something else, let us know!