How to properly format an 'if' statement being passed to a remote server in a when using 'while read'? - bash

Question

Ubuntu 18
Bash 4.4.0
I am wanting to pass an if statement to see whether or not a directory exist. If it does, I want to some commands and then a file. I have read through the similar posts but shellcheck complains about my formatting.
Script:
#!/bin/bash
testing="yes"
scriptDir="/root/.work"
wDir="${scriptDir}/.nginx-fix"
if [ "$testing" = "no" ]; then
hostfile="${scriptDir}/.zzz-hostnames"
else
hostfile="${scriptDir}/.zzz-hostnames-tester"
fi
cd "$wDir"
while read fqdn; do
{ clear; echo ""; echo ""; echo "$hostname"; echo ""; }
< /dev/null if ssh -p 34499 root#"${fqdn}" '[ -d /etc/nginx ]'; then
< /dev/null ssh -p 34499 root#"${fqdn}" 'mv /etc/nginx/nginx.conf /etc/nginx/.nginx-sept-30'
< /dev/null scp -P 34499 nginx.conf root#"${fqdn}":/etc/nginx
< /dev/null ssh -p 34499 root#"${fqdn}" 'sed -i "/honeypot/d" /etc/nginx/conf.d/*.conf'
< /dev/null ssh -p 34499 root#"${fqdn}" 'nginx -t'
else
exit 1;
fi
done<"${hostfile}"
Shellcheck complaint:
root#me ~/.work/.nginx-fix # shellcheck .nginx-fixer.sh
In .nginx-fixer.sh line 13:
while read fqdn; do
^-- SC1073: Couldn't parse this while loop.
^-- SC1061: Couldn't find 'done' for this 'do'.
In .nginx-fixer.sh line 15:
< /dev/null if ssh -p 33899 root#"${fqdn}" '[ -d /etc/nginx ]'; then
^-- SC1062: Expected 'done' matching previously mentioned 'do'.
^-- SC1072: Expected "#". Fix any mentioned problems and try again.
I'd appreciate your thoughts.

Answer 1

You can refactor the script to a clearer version and remove all the </dev/null:
while read -r fqdn; do {
{ clear; echo ""; echo ""; echo "$hostname"; echo ""; }
if ssh -p 34499 root#"${fqdn}" '[ -d /etc/nginx ]'; then
ssh -p 34499 root#"${fqdn}" 'mv /etc/nginx/nginx.conf /etc/nginx/.nginx-sept-30'
scp -P 34499 nginx.conf root#"${fqdn}":/etc/nginx
ssh -p 34499 root#"${fqdn}" 'sed -i "/honeypot/d" /etc/nginx/conf.d/*.conf'
ssh -p 34499 root#"${fqdn}" 'nginx -t'
else
exit 1;
fi
} </dev/null; done < "${hostfile}"
Almost invisible to the eye, I have put all the commands inside do ... done inside { .. } </dev/null. That way any command won't read from ${hostfile} and won't mess with while read.
Another option is to use a dedicated file descriptor and pass its number to read:
while read -r -u 10 fqdn; do
{ clear; echo ""; echo ""; echo "$hostname"; echo ""; }
if ssh -p 34499 root#"${fqdn}" '[ -d /etc/nginx ]'; then
ssh -p 34499 root#"${fqdn}" 'mv /etc/nginx/nginx.conf /etc/nginx/.nginx-sept-30'
scp -P 34499 nginx.conf root#"${fqdn}":/etc/nginx
ssh -p 34499 root#"${fqdn}" 'sed -i "/honeypot/d" /etc/nginx/conf.d/*.conf'
ssh -p 34499 root#"${fqdn}" 'nginx -t'
else
exit 1;
fi
done 10<"${hostfile}"

Answer 2

Running the script via 'bash -n' will indicate the 'real' error:
bash -n x.sh
x.sh: line 15: syntax error near unexpected token `then'
x.sh: line 15: ` < /dev/null if ssh -p 34499 root#"${fqdn}" '[ -d /etc/nginx ]' ; then'
You can not place redirection before on the 'if' statement. Move the redirection to the 'ssh' (condition part of the if) command, for example:
# USE:
if ssh < /dev/null -p 34499 root#"${fqdn}" '[ -d /etc/nginx ]' ; then'
# AND NOT:
< /dev/null if ssh -p 34499 root#"${fqdn}" '[ -d /etc/nginx ]' ; then'