How to check wether the current shell is running in a virtual terminal

disturb · 2010-07-13 16:45:17

I'm writing a simple bash function, which to be really useful, should be able determine wether the current shell is running in a virtual terminal or a tty.
Checking $TERM doesn't cut it, since it's not consistent, and I could be using screen, tmux or whatever...

Is there a way to do that ?

Bralkein · 2010-07-13 16:56:10

I think checking $DISPLAY might do what you want

jac · 2010-07-13 17:07:08

How about tty? Just look to see if it gives back something like /dev/tty* or /dev/pts/*

karol · 2010-07-13 19:22:10

By "shell" you mean f.e. bash?

[karol@black pbase]$ ps aux | grep bash | grep -v grep
karol     2823  0.0  0.1   5344  1944 tty1     S    01:05   0:00 bash
karol     2952  0.0  0.2   5456  2044 pts/5    S    01:18   0:00 bash
karol     4892  0.0  0.1   5344  1712 pts/7    S+   21:28   0:00 bash

Am I totally missing the point?

tavianator · 2010-07-13 19:35:19

@jac: "tty" still gives /dev/pts/* from within screen and tmux. Anyway, I'm not sure there's a good way to do this. Why do you want to?

PirateJonno · 2010-07-13 23:22:52

karol wrote:

By "shell" you mean f.e. bash?

For future reference, "for example" is traditionally abbreviated to "e.g."

karol wrote:

Am I totally missing the point?

Yes, since he wants to know the current shell, not a list of the ones running

milomouse · 2010-07-13 23:33:06

i used to use: ps $$, but i found this to be better:

ps --no-headers --format tty,comm $$

not sure if that's what you're looking for

EDIT: my mistake, didn't full read.
EDIT2: this code snippet should produce desired results, if not a variable of it.

Last edited by milomouse (2010-07-13 23:59:37)

karol · 2010-07-13 23:35:01

> not sure if that's what you're looking for
I don't think so - OP wants to know whether the script (or shell) is running in tty on under X - I think.

karol · 2010-07-13 23:38:37

[karol@black ~]$ ps aux | grep bash | grep grep
karol     5491  0.0  0.0   4332   692 pts/5    S+   01:46   0:00 grep bash

now I know the above command was run on pts/5.

Last edited by karol (2010-07-13 23:40:16)

milomouse · 2010-07-13 23:43:46

@karol: i'm pretty sure that's the same thing mine does but without grep. did you try it? open a few terminals and run that command in each one. it will show pts*/tty* of current shell. or try it in a script and do the same thing.

karol · 2010-07-13 23:50:28

@ milomouse
Cool, you saved me reading through the ps manpage - I knew there was a cleaner way to do it.
Your original post had 'ps --no-headers --format comm $$' and that didn't work, 'ps --no-headers --format tty,comm $$' does beautifully.

milomouse · 2010-07-13 23:52:16

Yeah, I made a quick edit probably after you read it, once I realized that the tty/pts was the important part. Glad it works, at least for us. We'll see if it's what op needs. :}

karol · 2010-07-13 23:54:53

Next time add

Edit: I fixed the command, now it works

instead of

EDIT: my mistake, didn't full read.

milomouse · 2010-07-13 23:58:55

Not to stray too far off topic, but I'm still not sure if that "works" for the op, but I'll edit my post anyway. Thanks for pointing that out.

fsckd · 2010-07-14 00:43:36

This is silly. Why are you guys emulating the tty command with ps?

In regards to OP's question there is no way for a program running under screen to figure out what type of terminal screen is running in. At least there is no straight forward way and it doesn't matter as some of the linux console's features would be blocked to programs.

PirateJonno · 2010-07-14 15:25:00

fsckd wrote:

In regards to OP's question there is no way for a program running under screen to figure out what type of terminal screen is running in. At least there is no straight forward way and it doesn't matter as some of the linux console's features would be blocked to programs.

What was wrong with checking if DISPLAY is set (mentioned above)?

fsckd · 2010-07-14 15:29:39

edit: DISPLAY will be set if screen were detached from a virtual terminal and reattached to the linux console. So no, not a perfect solution.

Last edited by fsckd (2010-07-14 15:35:22)

Arch Linux

#1 2010-07-13 16:45:17

How to check wether the current shell is running in a virtual terminal

#2 2010-07-13 16:56:10

Re: How to check wether the current shell is running in a virtual terminal

#3 2010-07-13 17:07:08

Re: How to check wether the current shell is running in a virtual terminal

#4 2010-07-13 19:22:10

Re: How to check wether the current shell is running in a virtual terminal

#5 2010-07-13 19:35:19

Re: How to check wether the current shell is running in a virtual terminal

#6 2010-07-13 23:22:52

Re: How to check wether the current shell is running in a virtual terminal

#7 2010-07-13 23:33:06

Re: How to check wether the current shell is running in a virtual terminal

#8 2010-07-13 23:35:01

Re: How to check wether the current shell is running in a virtual terminal

#9 2010-07-13 23:38:37

Re: How to check wether the current shell is running in a virtual terminal

#10 2010-07-13 23:43:46

Re: How to check wether the current shell is running in a virtual terminal

#11 2010-07-13 23:50:28

Re: How to check wether the current shell is running in a virtual terminal

#12 2010-07-13 23:52:16

Re: How to check wether the current shell is running in a virtual terminal

#13 2010-07-13 23:54:53

Re: How to check wether the current shell is running in a virtual terminal

#14 2010-07-13 23:58:55

Re: How to check wether the current shell is running in a virtual terminal

#15 2010-07-14 00:43:36

Re: How to check wether the current shell is running in a virtual terminal

#16 2010-07-14 15:25:00

Re: How to check wether the current shell is running in a virtual terminal

#17 2010-07-14 15:29:39

Re: How to check wether the current shell is running in a virtual terminal

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