How do I exit or cancel a bad bash command?

Question

I expect to get some flak for this, but I can't find the answer anywhere. It seems like it should be so obvious. Sometimes, when I type a bad command in a bash terminal, the cursor just jumps down to the next line without any error or anything. I can't tell what I did wrong. It's like I'm stuck in the program. Reenactment:

$ tidy

Me: "Oops! That's not what I meant to type..."

:q

Me: "That didn't work..."

:exit
:quit
exit
quit
/exit
/quit
-exit
-quit
-wtf???

I know I screwed up but how do I get back to the prompt without closing the terminal?

Related: What causes various signals to be sent? – Gilles 'SO- stop being evil' Aug 16 '12 at 23:23 — Gilles 'SO- stop being evil', Aug 16 '12 at 23:23
:q actually worked for me; isn't that a Vim command? – Nate Anderson Jan 12 '17 at 12:02 — Nate Anderson, Jan 12 '17 at 12:02

Levon · Accepted Answer · 2012-08-16T17:51:45.983

66

You can always try the obvious things like ^C, ^D (eof), Escape etc., but if all fails I usually end up suspending the command with ^Z (Control-Z) which puts me back into the shell.

I then do a ps command and note the PID (process id) of the command and then issue a kill thePID (kill -9 thePID if the former didn't work) command to terminate the application.

Note that this is not a tidy (no pun intended) way to terminate the application/command and you run the risk of perhaps no saving some data etc.

An example (I'd have used tidy but I don't have it installed):

$ gnuplot

    G N U P L O T
    Version 4.2 patchlevel 6 
     ....
    Send bug reports and suggestions to <http://sourceforge.net/projects/gnuplot>

Terminal type set to 'wxt'
gnuplot> 
gnuplot>               #####  typed ^Z here
[1]+  Stopped                 gnuplot
$ ps
  PID TTY          TIME CMD
 1681 pts/1    00:00:00 tcsh
 1690 pts/1    00:00:00 bash
 1708 pts/1    00:00:00 gnuplot
 1709 pts/1    00:00:00 ps


$ kill 1708            ###### didn't kill the command as ps shows

$ ps
  PID TTY          TIME CMD
 1681 pts/1    00:00:00 tcsh
 1690 pts/1    00:00:00 bash
 1708 pts/1    00:00:00 gnuplot
 1710 pts/1    00:00:00 ps
$ kill -9 1708           ### -9 did the trick
$ 
[1]+  Killed                  gnuplot

$ ps
  PID TTY          TIME CMD
 1681 pts/1    00:00:00 tcsh
 1690 pts/1    00:00:00 bash
 1711 pts/1    00:00:00 ps

edited Aug 16 '12 at 17:51

answered Aug 16 '12 at 17:37

Levon

11,384
4
45
41

10

That's it!! ^Z to the rescue. Thank you so much. – Big McLargeHuge Aug 16 '12 at 17:38
@davidkennedy85 Happy to help ... I was just cobbling together an example to post – Levon Aug 16 '12 at 17:39
3

^\ (ctrl-backslash, SIGQUIT) works in some stubborn utilities that don't respond to ^C. – mrb Aug 16 '12 at 19:11
2

Shh! Don't tell people about the ^\ or they'll start SIG_IGN'ing that too, then what will we do? – Alan Curry Aug 16 '12 at 19:55
I'd recommend ^Z, then kill %% to kill the job nicely, then kill -9 %% to kill it harshly if necessary. And using %% instead of using ps to find a pid is much easier. – godlygeek Nov 05 '14 at 19:12
1

@godlygeek Can you tell me what %% means in Linux or what kind of thing it is? I searched a lot. – Noumenon Jan 27 '16 at 17:17
1

@Noumenon, have a look at LESS='+/^JOB CONTROL' man bash. %% refers to the "current job". – Wildcard Mar 15 '16 at 01:49
kill -KILL <pid> or kill -SIGKILL <pid> is more readable than kill -9 <pid> – 12431234123412341234123 Sep 26 '16 at 10:19
What is the ^ key? – marsh Aug 05 '17 at 01:19
1

@marsh ^ is for control key, so ^Z would be Control-Z, ^C -> Control-C, etc .. ^Z suspends a command, ^C kills/terminates it. Hope that helps. – Levon Aug 05 '17 at 01:54

score 16 · Answer 2 · answered Aug 16 '12 at 17:37

16

Try pressing Ctrl-D or Ctrl-C. If it fails, kill the process .

Trying with the tidy command you mentioned, Ctrl-D works.

answered Aug 16 '12 at 17:37

Renan

17,136

1

CTRL+C is good for windows CMD too. – T.Todua Apr 30 '18 at 16:12

Gilles Quénot · Answer 3 · 2014-11-05T19:38:20.377

12

Another solution (not mentioned already) is to send the SIGQUIT signal using ctrl+\

It is stronger than a ctrl+c

edited Nov 05 '14 at 19:38

answered Nov 05 '14 at 19:24

Gilles Quénot

33,867

PersianGulf · Answer 4 · 2015-06-25T02:40:58.803

5

CTRL+D == exit shell command

and

CTRL+C == terminate the current process, Of course may be the given software handle it and CTRL+D doens't work

Of course , They produce a kernel signal if you want to know more, read :

man 7 signal

edited Jun 25 '15 at 02:40

answered Aug 16 '12 at 19:34

PersianGulf

10,850

4

Ctrl+D is end-of-file, not directly exit. – Gilles 'SO- stop being evil' Aug 16 '12 at 23:22

How do I exit or cancel a bad bash command?

4 Answers4