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Accepted
senorsmile
Asked: 2013-04-19 09:56:43 +0800 CST

bash: use outside variables when reading multiple lines into ssh

  • 772

I apologize if the title doesn't quite describe what I'm looking for. Please edit if possible.

I have a bash script that does the following:

serveruser="root"
serverip=1.2.3.4
serverpath="/var/www"


ssh "$serveruser"@"$serverip" /bin/bash <<\EOF
mkdir -p "$serverpath/mysqldumps/"
cd "$serverpath/mysqldumps/"
domainname=somedomain.com
mysqldump -h 192.168.1.4 -udba -ppassword -c --add-drop-table --add-locks --create-options --databases --quick --lock-tables $domainname > $domainname.sql
EOF

My problem is that the multiple lines I am "feeding" to ssh don't parse the variables I set before. This is obviously because the variables aren't set on the remote machine, only in my local shell. How could I pass these variables or possibly pass multiple lines to ssh in a different way?

mysql

3 Answers

  1. Best Answer

    The way you're escaping the here-doc word is preventing variable substitution. Contrast

    cat <<\END
$PATH
$LOGNAME
END

    versus

    cat <<END
$PATH
$LOGNAME
END

    update

    On closer inspection, I see you're setting a variable in the heredoc. That should not be expanded on the local machine, so you need to escape those in the mysqldump command. Try this:

    ssh "$serveruser"@"$serverip" <<EOF
mkdir -p "$serverpath/mysqldumps/"
cd "$serverpath/mysqldumps/"
domainname=somedomain.com
mysqldump -h 192.168.1.4 -udba -ppassword -c --add-drop-table --add-locks --create-options --databases --quick --lock-tables \$domainname > \$domainname.sql
EOF
    • 2 
  2. remote_user_name=user
instance_ip=127.0.0.1
external=$(ls /home/)

ssh -T -i ${private_key}  -l ${remote_user_name} ${instance_ip} << END
  internal=\$(ls /home/)
  echo "\${internal}"
  echo "${external}"
END
    • 0

  3. You need to quote the whole command.. and no need to quote the vars like that put them like ${var}

    serveruser="root"
serverip=1.2.3.4
serverpath="/var/www"


ssh ${serveruser}@${serverip} "/bin/bash <<\EOF
mkdir -p ${serverpath}/mysqldumps/
cd ${serverpath}/mysqldumps/
EOF"
    • -1