ssh $targetHost "[[ -z $(grep..." - fails. Why?

Question

[edit] per comment #1: more code, less description

Why doesn't this work as expected? ie: i want to :

ssh to a bunch of remote hosts in a loop (hence the </dev/null)
check if a setting is present in (the remote) rc.local (with grep)
if not then add it (with sed)

fail.sh

#!/bin/bash
targetHostList="
pizerocam0
pizerocam1
pizerocam2
pizerocam3
"
while IFS= read -r targetHost;do
    [[ -z $targetHost ]] && continue
    ssh -q $targetHost "[[ -f /etc/rc.local && -z $(grep -o '/usr/bin/tvservice -o' /etc/rc.local) ]] && sudo sed -Ei 's/exit\ 0/\/usr\/bin\/tvservice\ \-o \#\ disable HDMI\n\nexit\ 0/' /etc/rc.local"
done<<<"$targetHostList"

score 1 · Accepted Answer · answered Jan 04 '21 at 14:55

[SOLVED] Thanks Kamil! I just needed to see it. Knew it was what I wanted immediately. I'm sure i've done this before and just forgotten how.

SOLVED.sh

#!/bin/bash
targetHostList="
pizerocam0
pizerocam1
pizerocam2
pizerocam3
"
while IFS= read -r targetHost;do
    [[ -z $targetHost ]] && continue
ssh -q $targetHost bash <<'EOF'
[[ -f /etc/rc.local && -z $(grep -o '/usr/bin/tvservice -o' /etc/rc.local) ]] && sudo sed -Ei 's/exit\ 0//usr/bin/tvservice\ -o #\ disable HDMI\n\nexit\ 0/' /etc/rc.local
EOF
done<<<"$targetHostList"

ssh $targetHost "[[ -z $(grep..." - fails. Why?

1 Answers1