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Mulyadi Santosa [mulyadi.santosa at gmail.com]
For most people, to send a job to background after stopping a task, he/she will take a note the job ID and then invoke "bg" command appropriately like below:
$ (while (true); do yes > /dev/null ; done)
^Z
[2]+ Stopped ( while ( true ); do
yes > /dev/null;
done )
$ bg %2
[2]+ ( while ( true ); do
yes > /dev/null;
done ) &
Can we omit the job ID? Yes, we can. Simply replace the above "bg %2" with "bg %%". It will refer to the last stopped job ID. This way, command typing mistake could be avoided too.
-- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
Thomas Adam [thomas at xteddy.org]
On 22 February 2010 09:14, Mulyadi Santosa <mulyadi.santosa@gmail.com> wrote:
> For most people, to send a job to background after stopping a task, > he/she will take a note the job ID and then invoke "bg" command > appropriately like below: > > $ (while (true); do yes > /dev/null ; done) > ^Z > [2]+ Stopped ( while ( true ); do > yes > /dev/null; > done )
This is very shell-specific here in terms of output:
% xterm ^Z zsh: suspended xterm
> $ bg %2 > [2]+ ( while ( true ); do > yes > /dev/null; > done ) & > > Can we omit the job ID? Yes, we can. Simply replace the above "bg %2" > with "bg %%". It will refer to the last stopped job ID. This way, > command typing mistake could be avoided too.
Precisely -- which is where the "jobs" builtin is also useful:
% jobs -p [1] - 5317 running xterm [2] + 5452 running xterm
-- Thomas Adam
Ben Okopnik [ben at linuxgazette.net]
On Mon, Feb 22, 2010 at 04:14:09PM +0700, Mulyadi Santosa wrote:
> For most people, to send a job to background after stopping a task, > he/she will take a note the job ID and then invoke "bg" command > appropriately like below: > > $ (while (true); do yes > /dev/null ; done) > ^Z > [2]+ Stopped ( while ( true ); do > yes > /dev/null; > done ) > > $ bg %2 > [2]+ ( while ( true ); do > yes > /dev/null; > done ) & > > Can we omit the job ID? Yes, we can. Simply replace the above "bg %2" > with "bg %%". It will refer to the last stopped job ID. This way, > command typing mistake could be avoided too.
What's wrong with a simple 'bg'? The default, when you don't specify an argument, is the current job.
In my experience, specifying an arg to 'bg' or 'fg' is unnecessary 99% of the time - but that may just be the way that I use the job system, since I rarely have more than one thing backgrounded at any one time. The only place where I find '%%' useful is when it's coupled with 'kill': sometimes, a process that's not amenable to being stopped with 'Ctrl-C' will respond to a 'Ctrl-Z', after which it can be killed off with 'kill %%'.
-- * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *
Mulyadi Santosa [mulyadi.santosa at gmail.com]
Hi Ben...
On Mon, Feb 22, 2010 at 9:52 PM, Ben Okopnik <ben@linuxgazette.net> wrote:
> What's wrong with a simple 'bg'? The default, when you don't specify an > argument, is the current job.
Oh, you're right.....thanks, I just realized that after trying it by
myself. Fun, wish I knew it from long time ago 
-- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com