Passing a variable in a bash script to sshpass

Question

I am trying to pass a variable in a bash script to sshpass. Here is my code for reference:

NAME="HARRY"
sshpass -p passwd ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -q ipaddress 'bash -s' << 'EOF'
   echo $NAME
EOF

How can I pass the variable in a bash script to sshpass? Thank you!

Does this answer your question? Passing variable into sshpass command inside a script for loop — markp-fuso
– markp-fuso, Commented Aug 6, 2021 at 14:14
Public-key authentication would let you get rid of sshpass, making your script much simpler. — chepner
– chepner, Commented Aug 6, 2021 at 14:17
Agreed, sshpass isn't the most secure way. Also, if you repeat ssh conntections to the same server, consider adding a controlmaster with ssh option -o ControlMaster=auto -o ControlPersist=yes -o ControlPath=/var/run/ctrlm.%r@%h so you keep a persistent ssh connection for some time. This way next time you launch ssh, it keeps the already open connection from last time. By default, controlmasters are open 1H. — Orsiris de Jong
– Orsiris de Jong, Commented Aug 6, 2021 at 14:39

Dharman · Accepted Answer · 2021-08-06 14:22:26Z

0

Easiest way is using env just before running bash

NAME="HARRY"
sshpass -p passwd ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -q ipaddress env NAME="$NAME" 'bash -s' << 'EOF'
   echo $NAME
EOF

You can pass multiple variables with multiple env statements like

export NAME="HARRY"
export SOMEVAR="hello"
sshpass -p passwd ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -q ipaddress env NAME="$NAME" env SOMEVAR="$SOMEVAR" 'bash -s' << 'EOF'
   echo $NAME
EOF

Be aware that your variables might be interpreted when passing them. You can avoid that by changing env NAME="$NAME" to uninterpreted version env NAME="'$NAME'"

edited Aug 6, 2021 at 14:22

Dharman♦

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answered Aug 6, 2021 at 14:16

Orsiris de Jong

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2 Comments

chepner Over a year ago

This can cause its own problems, because now ssh has to combine env and all its arguments into a single string.

Orsiris de Jong Over a year ago

Indeed, best solution I found so far is singlequoting the variable in doublequotes to avoid unwanted interpetation.

Dominique · Accepted Answer · 2021-08-06 14:15:28Z

0

You can simply put a dollarsign in front of the variable name, as in this example:

Linux Prompt>cat test.txt
<here you see file content>
Linux Prompt>filename=test.txt
Linux Prompt>cat $filename
<here you see file content>

edited Aug 6, 2021 at 14:15

answered Aug 6, 2021 at 14:13

Dominique

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Comments

Barmar · Accepted Answer · 2021-08-06 14:13:48Z

-1

Put it after the -p option:

password=YourPassword
sshpass -p "$password" ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -q ipaddress 'bash -s' <<EOF
    echo "$NAME"
EOF

answered Aug 6, 2021 at 14:13

Barmar

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