String variable output showing strange Single Quote in Bash

Question

I have following scripts

#!/bin/bash
set -o xtrace
gluster_volume="a.example.com:/data/brick1/gv0 b.example.com:/data/brick1/gv0"
gluster volume create gv0 replica 2 ${gluster_volume} force

While executing second line this script throwing error related to gluster_volume that its unable read complete line and just considering a.example.com:/data/brick1/gv0 b.example.com(so look like gluster command not able parse it).

Then I run this script with trace and found that command is like

gluster volume create gv0 replica 2 'a.example.com:/data/brick1/gv0 b.example.com:/data/brick1/gv0' force

so script is adding single quotes which are creating problem. I was under the impression that it's due to set -o xtrace the single quotes are not part of the value, just part of the displayed command line. But its not true. if i run above command on command prompt it gives same error and on removing quotes it works.

How i can change my script so it don't add quotes? (I tried to remove quote with sed but not working, something happening at run time).

I need gluster_volume with dynamic values.

Update1:

workers=`echo "${WORKER_HOST_IP}"|sed "s/,$//"`
IFS=','
for worker in ${workers}; do
    IFS='-' read -r -a array <<< "$worker"

    gluster_volume+=${array[0]}':/data/brick1/gv0 '

done

Have you tried looking at this? stackoverflow.com/questions/9733338/… — TinkerTenorSoftwareGuy
– TinkerTenorSoftwareGuy, Commented Aug 6, 2020 at 16:11
Another option might be using the eval command... just concat the string to form the entire command, first. linuxhint.com/bash_eval_command — TinkerTenorSoftwareGuy
– TinkerTenorSoftwareGuy, Commented Aug 6, 2020 at 16:13
I suspect that you are not using bash but zsh. Add this to your script and its output to your question: echo "$BASH_VERSION". How do you start your script? — Cyrus
– Cyrus, Commented Aug 6, 2020 at 16:14
That IFS=',' explains it. You could reset IFS back to normal after the loop (there are several ways to do this, none perfect), but I'd look at using a better method to split workers. The best way to do that depends on the exact format of the WORKER_HOST_IP variable. — Gordon Davisson
– Gordon Davisson, Commented Aug 7, 2020 at 19:49

Aravinda VK · Accepted Answer · 2020-09-16 10:35:49Z

1

You can try eval(Be careful if the list of bricks or the string comes from an external untrusted source)

#!/bin/bash
set -o xtrace
gluster_volume="a.example.com:/data/brick1/gv0 b.example.com:/data/brick1/gv0"
eval "gluster volume create gv0 replica 2 ${gluster_volume} force"

answered Sep 16, 2020 at 10:35

Aravinda VK

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