Cela peut par exemple vous servir pour gérer ou retrouver vos tunnel.
Extrait du man :
ESCAPE CHARACTERS When a pseudo-terminal has been requested, ssh supports a number of func- tions through the use of an escape character. A single tilde character can be sent as ~~ or by following the tilde by a character other than those described below. The escape character must always follow a newline to be interpreted as special. The escape charac- ter can be changed in configuration files using the EscapeChar configura- tion directive or on the command line by the -e option. The supported escapes (assuming the default `~') are: ~. Disconnect. ~^Z Background ssh. ~# List forwarded connections. ~& Background ssh at logout when waiting for forwarded connection / X11 sessions to terminate. ~? Display a list of escape characters. ~B Send a BREAK to the remote system (only useful for SSH protocol version 2 and if the peer supports it). ~C Open command line. Currently this allows the addition of port forwardings using the -L, -R and -D options (see above). It also allows the cancellation of existing port-forwardings with -KL[<em>bind_address</em>:]<em>port</em> for local, -KR[<em>bind_address</em>:]<em>port</em> for re- mote and -KD[<em>bind_address</em>:]<em>port</em> for dynamic port-forwardings. !<em>command</em> allows the user to execute a local command if the PermitLocalCommand option is enabled in <a href="http://man.openbsd.org/">ssh_config(5)</a>. Basic help is available, using the -h option. ~R Request rekeying of the connection (only useful for SSH protocol version 2 and if the peer supports it).