Question

I’m new here and I’ll do my best to explain my problem 🙂

I want to write a backup script to save all lv‘s used by KVM.

OS: Ubuntu Server x64 12.04

Bash 4.2.24

XML file content:

<source file='/dev/vg1/lv1'/>
<source file='/dev/vg1/lv2'/>

My grep/cut command

grep "<source file='.*.'/>" /backup/$SRCNAME/$DATUM/$SRCNAME.xml | cut -f2 -d"'" | cut -f4 -d"/"

This outputs

lv1
lv2

How do I get it to do something with each output – is storing the output in an array the best way?

I’ve been searching for an answer for 2 days now 🙁 I’ve tried some loops and pipes, but nothing worked because my grep command is too specific :/

Answer 1

To save it into an array:

array=( $(grep "<source file='.*.'/>" /backup/$SRCNAME/$DATUM/$SRCNAME.xml | cut -f2 -d"'" | cut -f4 -d"/")

You can also pipe this into a loop:

grep "<source file='.*.'/>" /backup/$SRCNAME/$DATUM/$SRCNAME.xml | cut -f2 -d"'" | cut -f4 -d"/" | while read lv; do
    echo "$lv"
done

Note however, that because of the piping, the loop may run in a sub-shell, so changes to variables won’t propagate back to the parent shell.

Hope this helps =)