1999-04-15 20:05:35 +02:00
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texinode(Jobs & Signals)(Arithmetic Evaluation)(Functions)(Top)
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chapter(Jobs & Signals)
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sect(Jobs)
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cindex(jobs)
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2001-07-10 10:59:17 +02:00
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pindex(MONITOR, use of)
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1999-04-15 20:05:35 +02:00
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If the tt(MONITOR) option is set,
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an interactive shell associates a em(job) with each pipeline.
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It keeps a table of current jobs, printed by the tt(jobs)
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command, and assigns them small integer numbers.
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When a job is started asynchronously with `tt(&)',
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2004-07-02 16:59:04 +02:00
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the shell prints a line to standard error which looks like:
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1999-04-15 20:05:35 +02:00
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2000-10-14 02:14:15 +02:00
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example([1] 1234)
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1999-04-15 20:05:35 +02:00
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indicating that the job which was started asynchronously was job number
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1 and had one (top-level) process, whose process ID was 1234.
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If a job is started with `tt(&|)' or `tt(&!)',
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then that job is immediately disowned. After startup, it
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does not have a place in the job table, and is not subject
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to the job control features described here.
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If you are running a job and wish to do something else you may hit the key
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2000-10-14 02:14:15 +02:00
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^Z (control-Z) which sends a tt(TSTP) signal to the current job: this key
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may be redefined by the tt(susp) option of the external tt(stty) command.
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1999-04-15 20:05:35 +02:00
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cindex(jobs, suspending)
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cindex(suspending jobs)
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The shell will then normally indicate that the job has been `suspended',
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and print another prompt. You can then manipulate the state of this job,
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findex(bg, use of)
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putting it in the background with the tt(bg) command, or run some other
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commands and then eventually bring the job back into the foreground with
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findex(fg, use of)
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the foreground command tt(fg). A ^Z takes effect immediately and
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is like an interrupt in that pending output and unread input are discarded
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when it is typed.
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A job being run in the background will suspend if it tries to read
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from the terminal.
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cindex(background jobs, I/O)
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cindex(jobs, background, I/O)
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Background jobs are normally allowed to produce output,
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but this can be disabled by giving the command `tt(stty tostop)'.
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If you set this
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tty option, then background jobs will suspend when they try to produce
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output like they do when they try to read input.
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2000-10-14 02:14:15 +02:00
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When a command is suspended and continued later with the tt(fg) or
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tt(wait) builtins, zsh restores tty modes that were in effect when it was
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suspended. This (intentionally) does not apply if the command is
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continued via `tt(kill -CONT)', nor when it is continued with tt(bg).
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1999-04-15 20:05:35 +02:00
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cindex(jobs, referring to)
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cindex(referring to jobs)
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There are several ways to refer to jobs in the shell.
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A job can be referred to by the process ID of any process of the job
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or by one of the following:
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startsitem()
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sitem(tt(%)var(number))(The job with the given number.)
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sitem(tt(%)var(string))(Any job whose command line begins with var(string).)
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sitem(tt(%?)var(string))(Any job whose command line contains var(string).)
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sitem(tt(%%))(Current job.)
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sitem(tt(%PLUS()))(Equivalent to `tt(%%)'.)
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sitem(tt(%-))(Previous job.)
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endsitem()
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The shell learns immediately whenever a process changes state.
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pindex(NOTIFY, use of)
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It normally informs you whenever a job becomes blocked so that
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no further progress is possible. If the tt(NOTIFY) option is not set,
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it waits until just before it prints a prompt before it informs you.
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2004-07-02 16:59:04 +02:00
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All such notifications are sent directly to the terminal, not to
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the standard output or standard error.
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1999-04-15 20:05:35 +02:00
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When the monitor mode is on, each background job that completes
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triggers any trap set for tt(CHLD).
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When you try to leave the shell while jobs are running or suspended, you will
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be warned that `You have suspended (running) jobs'.
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You may use the tt(jobs) command to see what they are.
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If you do this or immediately try to
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exit again, the shell will not warn you a second time; the suspended
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jobs will be terminated, and the running jobs will be sent
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a tt(SIGHUP) signal, if the tt(HUP) option is set.
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pindex(HUP, use of)
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cindex(jobs, disowning)
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cindex(disowning jobs)
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findex(disown, use of)
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To avoid having the shell terminate the running jobs, either
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use the bf(nohup) command (see manref(nohup)(1))
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or the tt(disown) builtin.
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sect(Signals)
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The tt(INT) and tt(QUIT) signals for an invoked
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command are ignored if the command is followed by
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`tt(&)' and the tt(MONITOR) option is not active.
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Otherwise, signals have the values
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inherited by the shell from its parent
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(but see the tt(TRAP)var(NAL) special functions in noderef(Functions)).
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