This post describes how you can set up the automation app Tasker on android to run a command on a remote host via SSH, without the need to enter a password. We will discuss two options: The first one will just run a command, the second one can additionally return a value, but will require a paid plug-in.

Option 1: Run a remote command via ConnectBot

  1. Install the free SSH client ConnectBot.
  2. We need to set up key-based authentication with ConnectBot, and there are already tutorials on that, for example this one.
  3. When you have set up the connection, long-press the connection in ConnectBot’s host list and select Edit host. Change the name to some nickname, e.g., myconnection.
  4. Configure the post-login automation. Enter the command or script you’d like to run followed by a semicolon, exit and enter, e.g.: /home/me/; exit ↩. This is to make sure ConnectBot just runs the command and returns.
  5. Now let’s use it in Tasker. Create a Task, select +, System, Send Intent. Configure the action as follows:
    • Action: android.intent.action.VIEW
    • Cat: None
    • Data: ssh://user@host:port#myconnection
    • Target: Activity

When you run the Task, the remote command should execute. Note that for every different command you want to run on the host, you need to create a separate profile in ConnectBot, with different nicknames.

Option 2: Run a remote command and return its output to Tasker

This option requires the SSH Tasker Plugin. Note that there is also a Lite Version of the plug-in, but that one doesn’t execute arbitrary commands.

  1. The SSH Plugin can not reuse ConnectBot’s key file format, so we need to create a key pair on the target host. Log in to the host and run ssh-keygen -t rsa. The command will ask where to save the file, select one that you will recognize for usage in Tasker, e.g., /home/me/.ssh/id_rsa-tasker. When asked for a passphrase, enter a good passphrase.
  2. Authorize the key: cat ~/.ssh/ >> ~/.ssh/authorized_keys
  3. Copy the file ~/.ssh/id_rsa-tasker to you android device somehow. One method is via the free ES File Explorer that also allows to copy files via SSH.
  4. In Tasker, create a Task, select +, Plugin, SSH Plugin Paid.
  5. Configure the Action:
    • Enter username and host
    • For Keypair File Location, select the id_rsa-tasker file that you copied to your device
    • For Encrypted Keyfile Password, enter the passphrase you selected during ssh-keygen
    • Enter the remote command followed by a semicolon
    • Switch on “Return Output”
    • In the last field, enter the name of a Tasker variable to bind to, e.g., %result.
  6. Now you can use the local %result variable in subsequent actions of the task. The following steps are only required, if the executed command returns a line of text, and you need to get rid of the trailing newline.
  7. After the SSH Plugin action, add a Variable Set action, set its name to %newline and in its value field, enter a literal line break, i.e., press ↩.
  8. Add a Variable Split action, set its name to %result and splitter to %newline.
  9. Now you will have the result of the command without its trailing newline bound to the variable %result1.

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