<HTML> <HEAD> <!-- Created by texi2html 1.56k from ./zsh.texi on 26 June 2001 --> <TITLE>zsh - Jobs & Signals</TITLE> </HEAD> <BODY> Go to the <A HREF="zsh_1.html">first</A>, <A HREF="zsh_8.html">previous</A>, <A HREF="zsh_10.html">next</A>, <A HREF="zsh_29.html">last</A> section, <A HREF="zsh_toc.html">table of contents</A>. <P><HR><P> <H1><A NAME="SEC34" HREF="zsh_toc.html#TOC34">Jobs & Signals</A></H1> <P> <H2><A NAME="SEC35" HREF="zsh_toc.html#TOC35">Jobs</A></H2> <P> <A NAME="IDX100"></A> If the <TT>MONITOR</TT> option is set, an interactive shell associates a <EM>job</EM> with each pipeline. It keeps a table of current jobs, printed by the <TT>jobs</TT> command, and assigns them small integer numbers. When a job is started asynchronously with `<TT>&</TT>', the shell prints a line which looks like: <P> <PRE> [1] 1234 </PRE> <P> indicating that the job which was started asynchronously was job number 1 and had one (top-level) process, whose process ID was 1234. <P> If a job is started with `<TT>&|</TT>' or `<TT>&!</TT>', then that job is immediately disowned. After startup, it does not have a place in the job table, and is not subject to the job control features described here. <P> If you are running a job and wish to do something else you may hit the key ^Z (control-Z) which sends a <TT>TSTP</TT> signal to the current job: this key may be redefined by the <TT>susp</TT> option of the external <TT>stty</TT> command. <A NAME="IDX101"></A> <A NAME="IDX102"></A> The shell will then normally indicate that the job has been `suspended', and print another prompt. You can then manipulate the state of this job, <A NAME="IDX103"></A> putting it in the background with the <TT>bg</TT> command, or run some other commands and then eventually bring the job back into the foreground with <A NAME="IDX104"></A> the foreground command <TT>fg</TT>. A ^Z takes effect immediately and is like an interrupt in that pending output and unread input are discarded when it is typed. <P> A job being run in the background will suspend if it tries to read from the terminal. <A NAME="IDX105"></A> <A NAME="IDX106"></A> Background jobs are normally allowed to produce output, but this can be disabled by giving the command `<TT>stty tostop</TT>'. If you set this tty option, then background jobs will suspend when they try to produce output like they do when they try to read input. <P> When a command is suspended and continued later with the <TT>fg</TT> or <TT>wait</TT> builtins, zsh restores tty modes that were in effect when it was suspended. This (intentionally) does not apply if the command is continued via `<TT>kill -CONT</TT>', nor when it is continued with <TT>bg</TT>. <P> <A NAME="IDX107"></A> <A NAME="IDX108"></A> There are several ways to refer to jobs in the shell. A job can be referred to by the process ID of any process of the job or by one of the following: <P> <DL COMPACT> <DT><TT>%</TT><VAR>number</VAR> <DD> The job with the given number. <DT><TT>%</TT><VAR>string</VAR> <DD> Any job whose command line begins with <VAR>string</VAR>. <DT><TT>%?</TT><VAR>string</VAR> <DD> Any job whose command line contains <VAR>string</VAR>. <DT><TT>%%</TT> <DD> Current job. <DT><TT>%+</TT> <DD> Equivalent to `<TT>%%</TT>'. <DT><TT>%-</TT> <DD> Previous job. </DL> <P> The shell learns immediately whenever a process changes state. <A NAME="IDX109"></A> It normally informs you whenever a job becomes blocked so that no further progress is possible. If the <TT>NOTIFY</TT> option is not set, it waits until just before it prints a prompt before it informs you. <P> When the monitor mode is on, each background job that completes triggers any trap set for <TT>CHLD</TT>. <P> When you try to leave the shell while jobs are running or suspended, you will be warned that `You have suspended (running) jobs'. You may use the <TT>jobs</TT> command to see what they are. If you do this or immediately try to exit again, the shell will not warn you a second time; the suspended jobs will be terminated, and the running jobs will be sent a <TT>SIGHUP</TT> signal, if the <TT>HUP</TT> option is set. <A NAME="IDX110"></A> <P> <A NAME="IDX111"></A> <A NAME="IDX112"></A> <A NAME="IDX113"></A> To avoid having the shell terminate the running jobs, either use the <CITE>nohup</CITE> command (see man page nohup(1)) or the <TT>disown</TT> builtin. <H2><A NAME="SEC36" HREF="zsh_toc.html#TOC36">Signals</A></H2> <P> The <TT>INT</TT> and <TT>QUIT</TT> signals for an invoked command are ignored if the command is followed by `<TT>&</TT>' and the <TT>MONITOR</TT> option is not active. Otherwise, signals have the values inherited by the shell from its parent (but see the <TT>TRAP</TT><VAR>NAL</VAR> special functions in section <A HREF="zsh_8.html#SEC31">Functions</A>). <P><HR><P> Go to the <A HREF="zsh_1.html">first</A>, <A HREF="zsh_8.html">previous</A>, <A HREF="zsh_10.html">next</A>, <A HREF="zsh_29.html">last</A> section, <A HREF="zsh_toc.html">table of contents</A>. </BODY> </HTML>
