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Run a command (or a snippet) on multiple hosts

What is it?

Since WebSSH 33.0, a snippet — or a command typed for the occasion — can be run on several saved connections at once. WebSSH connects to each host in the background, runs the command without opening a terminal, and gathers every result in a single report: status, exit code, duration and output, host by host.

Where to start from

There are three ways to open the Run on Hosts sheet:

  1. From a snippet: in the Snippets section, tap a snippet (or choose Run on Hosts in its context menu; editing is there too). The hosts linked to the snippet through tags are preselected.
  2. From a selection of servers: in the Servers section, choose Select in the ⋯ menu, tick the hosts, then tap the ▶︎ button in the navigation bar. The selection is preselected and you then pick a snippet, or type a command.
  3. From the Servers menu: choose Run on Hosts… in the ⋯ menu of the Servers section, then pick everything in the sheet.

The sheet

  • What to run: a saved Snippet (chosen from your library), or a one-shot Command typed in the field. The last ten one-shot commands are kept under Recent commands; a one-shot command can later be turned into a snippet from the report (Save as snippet).
  • Where to run: your SSH connections, grouped by folder, with a search field, tag chips and Select all buttons. Telnet and port forwarding entries are not listed.
  • Settings: how many hosts run in parallel (1 to 8, default 4) and an optional timeout per host (none by default, up to 1 h): a long apt upgrade is never cut short by a guess, and Stop is always there for a command that hangs. Both are remembered.

Tap Run on N hosts. If the command uses dynamic variables, the usual form appears once: the values you type apply to every host. The built-in variables ({{{ HOST }}}, {{{ USER }}}, {{{ PORT }}}, {{{ CONNECTION }}}, {{{ DATE }}}) are not asked: they are filled per host from each connection.

Confirmation

Before anything is sent, WebSSH shows the command (secret values masked) and the list of hosts. When the command looks destructive (rm -rf, mkfs, reboot, apt … -y, docker prune, qm destroy…), the sheet turns red and asks for a second tap: there is no undo on twenty servers.

The report

The report is a session like any other: it stays listed in the sidebar (and in the windows menu on iPhone) while the run is alive, and you can leave it and come back.

  • A summary: hosts done, failed and left, a progress bar, the elapsed time.
  • One row per host: status, exit code, duration; tap it to see the output (stdout and stderr, colours stripped), live while the command runs. Long press a row to copy its output or its command.
  • The ⋯ menu: Re-run failed hosts, Re-run all hosts, Copy full report, Share (a text file), Save as snippet for a one-shot command.
  • Stop cancels the hosts still waiting and tears down the commands still running.

Each host connection is closed as soon as its command ends: nothing stays open once the report is complete.

How hosts are connected

Every host goes through the same pipeline as a terminal session: ssh_config overrides, private keys, jump hosts, port knocking, DNS strategy… Connections are established one after the other — so that a password or host key prompt never collides with another one — and the commands then run in parallel, up to the number of hosts you chose. A prompt (unknown host key, missing password, challenge) is shown for the host that needs it; cancelling it marks that host as Cancelled and the run goes on with the others.

Limits

  • No terminal, no PTY: the command runs on an SSH exec channel. Interactive programs (top, vim, tmux…), sudo asking for a password and any prompt will block until the timeout. Prefer sudo -n, apt-get -y, DEBIAN_FRONTEND=noninteractive… or set up NOPASSWD in sudoers.
  • Snippets sending key strokes (<ctrl-…>, <esc>, <tab>…) are refused: they need a terminal.
  • Timeout: off by default. When set, a command still running after the timeout is stopped (the channel is closed, which ends the remote process) and reported as Timed out.
  • Output is kept up to 256 KB per host.
  • mosh and Telnet connections are not eligible.

Interactive work on a few hosts

When you need to see and drive what happens (an upgrade asking questions, for example), open the sessions side by side on iPad or Mac and use Terminal Broadcast Input (⌥⌘B): what you type goes to every pane.

Last update: September 23, 2026