5.4 Declaring multiple hops in the file name

TRAMP file name syntax can accommodate ad-hoc specification of multiple proxies without using tramp-default-proxies-alist configuration setup (see Connecting to a remote host using multiple hops).

Each proxy is specified using the same syntax as the remote host specification minus the file name part. Each hop is separated by a ‘|’. Chain the proxies from the starting host to the destination remote host name and file name. For example, hopping over a single proxy ‘bird@bastion’ to a remote file on ‘you@remotehost’:

C-x C-f /ssh:bird@bastion|ssh:you@remotehost:/path RET

Each involved method must be an inline method (see Inline methods).

TRAMP adds the ad-hoc definitions on the fly to tramp-default-proxies-alist and is available for reuse during that Emacs session. Subsequent TRAMP connections to the same remote host can then use the shortcut form: ‘/ssh:you@remotehost:/path’.

User Option: tramp-show-ad-hoc-proxies

If this user option is non-nil, ad-hoc definitions are kept in remote file names instead of showing the shortcuts.

(customize-set-variable 'tramp-show-ad-hoc-proxies t)

Ad-hoc definitions are removed from tramp-default-proxies-alist via the command M-x tramp-cleanup-all-connections RET (see Cleanup remote connections).

User Option: tramp-save-ad-hoc-proxies

For ad-hoc definitions to be saved automatically in tramp-default-proxies-alist for future Emacs sessions, set tramp-save-ad-hoc-proxies to non-nil.

(customize-set-variable 'tramp-save-ad-hoc-proxies t)

Ad-hoc proxies can take patterns %h or %u like in tramp-default-proxies-alist. The following file name expands to user ‘root’ on host ‘remotehost’, starting with an ssh session on host ‘remotehost’: ‘/ssh:%h|su:remotehost:’.

On the other hand, if a trailing hop does not specify a host name, the host name of the previous hop is reused. Therefore, the following file name is equivalent to the previous example: ‘/ssh:remotehost|su::’.