Screen terminal multiplexer: Difference between revisions
Dubiousjim (talk | contribs) (delete Category:Networking) |
(Restructuring a bit. Adding some notes and examples that indicates how screen can be used) |
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{{pkg|screen}} is a good tool for remote support. It can also be used to start a command you want to keep running after you close your console session (you can later on attach to your running {{pkg|screen}} session). When you enter a {{pkg|screen}} session you will not notice too much.<BR> | |||
To know if you are inside a | To know if you are inside a {{pkg|screen}} session, use the notes in '[[#Get_help|get help]]' section mentioned below. | ||
= Install = | = General = | ||
== Install == | |||
In order to use {{pkg|screen}} you will have to install it: | |||
{{cmd|apk add screen}} | {{cmd|apk add screen}} | ||
= | = Usage = | ||
== Start a new session == | == Start a new session == | ||
To enter a {{pkg|screen}} session you just enter: | |||
{{cmd|screen}} | {{cmd|screen}} | ||
== List existing sessions == | == List existing sessions == | ||
When you have started some session(s) you can list them: | |||
{{cmd|screen -list}} | {{cmd|screen -list}} | ||
You might get a list that looks like this: | You might get a list that looks like this: | ||
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== Attach to a existing session == | == Attach to a existing session == | ||
Lets say you want to attach to a existing session (e.g. the above | Lets say you want to attach to a existing session (e.g. the above <code>11131.pts-3.mhlab01</code> session). | ||
{{cmd|screen -x 11131}} | {{cmd|screen -x 11131}} | ||
or | or | ||
{{cmd|screen -x pts-3}} | {{cmd|screen -x pts-3}} | ||
{{tip|If you see <code>Attaching from inside of screen?</code>, you are allready inside a screen session.}} | |||
== Controlling a screen session == | |||
While inside a {{pkg|screen}} session, you can controll it using keyboard shortcuts. We will only describe some of those alternatives. | |||
{{tip|To enter a keyboard shortcut that controls the current {{pkg|screen}} session, you should click {{key|A}} while holding down {{key|CTRL}}<br>In the below examples this procedure is described as <code>^A</code>}} | |||
=== Get help === | |||
One of the most useful commands is the one that gives you 'help'.<br> | |||
While in your {{pkg|screen}} session, click: | |||
{{cmd|^A ?}} | |||
''(Do not press/hold {{key|CTRL}} when clicking {{key|?}})'' | |||
=== Detach from a session === | |||
Sometimes it's useful to just detach from a session without killing it.<br> | |||
{{cmd|^A d}} | |||
{{tip|Try starting <code>ping 127.0.0.1</code> while inside a screen session and then detatch from the session.<br>After some while re-connect to the session using <code>screen -x</code>.<br>Note that the "seq" value indikates that ping had continued running while you where detatched from the session.}} | |||
== Close or kill a session == | === Close or kill a session === | ||
To 'kill' a session: | |||
{{cmd| | {{cmd|^A k}} | ||
Confirm by clicking {{key|y}} when prompted. | |||
You can also 'kill' you session by entering: | |||
{{cmd|exit}} | {{cmd|exit}} | ||
= Extra = | = Extra = | ||
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In some cases you might want to force only console users into a screen session.<BR> | In some cases you might want to force only console users into a screen session.<BR> | ||
Note that the this configuration will not force SSH-users into a screen.<BR> | Note that the this configuration will not force SSH-users into a screen.<BR> | ||
Edit | Edit {{path|/etc/profile}} and add the following code to it: | ||
<pre> | <pre> | ||
if [ -n "$PS1" ] && [ -z "$STARTED_SCREEN" ] && [ -z "$SSH_TTY" ]; then | if [ -n "$PS1" ] && [ -z "$STARTED_SCREEN" ] && [ -z "$SSH_TTY" ]; then | ||
Revision as of 10:05, 24 October 2012
screen is a good tool for remote support. It can also be used to start a command you want to keep running after you close your console session (you can later on attach to your running screen session). When you enter a screen session you will not notice too much.
To know if you are inside a screen session, use the notes in 'get help' section mentioned below.
General
Install
In order to use screen you will have to install it:
apk add screen
Usage
Start a new session
To enter a screen session you just enter:
screen
List existing sessions
When you have started some session(s) you can list them:
screen -list
You might get a list that looks like this:
There are screens on:
11151.pts-1.mhlab01 (Attached)
11131.pts-3.mhlab01 (Attached)
2 Sockets in /var/run/screen/S-root.
Attach to a existing session
Lets say you want to attach to a existing session (e.g. the above 11131.pts-3.mhlab01 session).
screen -x 11131
or
screen -x pts-3
Attaching from inside of screen?, you are allready inside a screen session.Controlling a screen session
While inside a screen session, you can controll it using keyboard shortcuts. We will only describe some of those alternatives.
In the below examples this procedure is described as
^AGet help
One of the most useful commands is the one that gives you 'help'.
While in your screen session, click:
^A ?
(Do not press/hold CTRL when clicking ?)
Detach from a session
Sometimes it's useful to just detach from a session without killing it.
^A d
ping 127.0.0.1 while inside a screen session and then detatch from the session.After some while re-connect to the session using
screen -x.Note that the "seq" value indikates that ping had continued running while you where detatched from the session.
Close or kill a session
To 'kill' a session:
^A k
Confirm by clicking y when prompted.
You can also 'kill' you session by entering:
exit
Extra
Force console users into a screen session
In some cases you might want to force only console users into a screen session.
Note that the this configuration will not force SSH-users into a screen.
Edit /etc/profile and add the following code to it:
if [ -n "$PS1" ] && [ -z "$STARTED_SCREEN" ] && [ -z "$SSH_TTY" ]; then STARTED_SCREEN=1 ; export STARTED_SCREEN screen -RR && exit 0 echo "Screen failed! continuing with normal bash startup" fi
Force console and SSH users into a screen session
The above example holds the if-statement:
&& [ -z "$SSH_TTY" ]
Remove this part from above configuration to force SSH sessions into a screen session.