The trap tag has no wiki summary.
5
votes
1answer
339 views
“trap … INT TERM EXIT” really necessary?
Many examples for trap use trap ... INT TERM EXIT for cleanup tasks. But is it really necessary to list all the three sigspecs?
The manual says:
If a SIGNAL_SPEC is EXIT (0) ARG is executed on ...
4
votes
3answers
227 views
Silently start task in background
I know that you can use this to start a process in the background, without getting the notification when the process is put in the background and when it is done like so:
(command &) &> /dev/null
...
3
votes
3answers
1k views
Error handling in shell script
I wrote a shell script run_script.sh, which includes a step which creates an empty file run_script.lck. Everytime the shell script was called by the cronjob, it will check for the existence of ...
3
votes
3answers
2k views
How to stop the loop bash script in terminal?
For example,
#!/bin/bash
while :
do
sl
done
How to terminate this bash script?
3
votes
2answers
359 views
Wrapper program that sets signal handler
I would like to have a wrapper program that runs a given command and sets a signal handler so that it gets run when the command receives a specified signal.
The question is this:
Is there an ...
3
votes
3answers
1k views
How to setup trap in bash functions?
I can setup trap in bash scripts but not bash functions.
For example, source the code below and run f, now try Ctrl+C, it's not been trapped!
How to setup trap in bash functions?
4 trap ctrl_c ...
3
votes
2answers
1k views
How can I trap a program that returns 139 (segmentation fault) in bash?
I have a bash script that tests some programs and one of the program returns Segmentation fault so I tried to add a trap in the head of my script:
trap "echo 'segfault occured!'" SIGSEGV
That ...
3
votes
1answer
576 views
Intercept “command not found” error in zsh
Is there a way to intercept the "command not found" error in ZSH? I've seen this is possible in bash apparently, but I couldn't find anything about doing it in zsh.
3
votes
2answers
58 views
Text files with sections in common with a given file
I need to maintain a set of plain text files saved in a directory which all have a section taken from another file. An example follows:
Files:
/directory/textfile1 (every other file in the directory ...
3
votes
2answers
242 views
Bash: keybinding/trap issue
My .bashrc has the following:
# Alt+L lists current directory
bind -x "\"\el\":ls -ltrF --color=auto;"
# trap commands and echo them to xterm titlebar.
trap 'echo -ne "\033]0;$BASH_COMMAND - ...
2
votes
1answer
1k views
What is signal 0 in a trap command?
I'm following this guide on how to set up passwordless SSH authentication with ssh-agent.
To start up ssh-agent the author recommends the following code in .bash_profile:
SSHAGENT=/usr/bin/ssh-agent
...
2
votes
1answer
46 views
Confirm before exit the command-prompt
I am trying to have a confirmation message every time I type exit command in the command-prompt. To do this, I have tried to use trap in .bashrc file but it seem like trap is not a solution as it run ...
2
votes
1answer
144 views
Why doesn't an orphan process receive signals?
I have two shell scripts: launch_job.sh and sub_job.sh.
If launch_job.sh uses the following method to run sub_job.sh:
nohup sub_job.sh &
sub_job.sh becomes an orphan, i.e. with PPID 1.
I ...
1
vote
1answer
493 views
Trap, ERR, and echoing the error line
I'm trying to create some error reporting using a Trap to call a function on all errors:
Trap "_func" ERR
Is it possible to get what line the ERR signal was sent from? The shell is bash.
If I do ...
1
vote
2answers
813 views
how to trap a suspend a resume from a bash script
I have a bash script (on osx) running continuously, it currently traps and handles a terminate like so
trap onshutdown TERM
how can I make trap also handle suspend/resume like
trap onsuspend ?
...
0
votes
0answers
109 views
Trap signals by an external shell on bash?
I tried to do this script:
#!/bin/bash
trap "echo trapped!" SIGUSR2
sleep 3s
kill -SIGUSR2 $$;
exit 0
and it works because it kills itself "from the inner".
if i try this
#!/bin/bash
trap "echo ...
