Support the SUSv3 -n option and the "--" end of options marker.
Replace "command" with "utility" in the manual page & source to be more consistent with the terminology used in the standard, and to hint that shell builtin commands won't work. Submitted by: Peter Avalos <pavalos@theshell.com> (partially) Approved by: mike
This commit is contained in:
Tim J. Robbins
parent
386f1d1bf2
commit
7e91d5f926
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=96481
@ -37,40 +37,26 @@
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.Os
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.Sh NAME
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.Nm nice
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.Nd execute a command at a low scheduling priority
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.Nd execute a utility at an altered scheduling priority
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.Sh SYNOPSIS
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.Nm
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.Op Fl Ns Ar number
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.Ar command
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.Op Ar arguments
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.Op Fl n Ar increment
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.Ar utility
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.Op Ar argument ...
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.Sh DESCRIPTION
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The
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.Nm
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utility runs
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.Ar command
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at a low priority.
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(Think of low and slow).
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If
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.Fl Ns Ar number
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is not given,
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.Nm
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assumes the value 10.
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The priority is a value in the range -20 to 20.
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The default priority is 0, priority 20 is the lowest possible.
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The
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.Nm
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utility will execute
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.Ar command
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at priority
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.Ar number
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relative to the priority
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of
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.Nm .
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Higher priorities than the
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current process priority can only requested by the
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super-user.
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Negative numbers are expressed as
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.Fl - Ns Ar number .
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.Ar utility
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at an altered scheduling priority, by incrementing its
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.Dq nice
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value by the specified
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.Ar increment ,
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or a default value of 10.
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The lower the nice value of a process, the higher its scheduling priority.
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.Pp
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The superuser may specify a negative increment in order to run a utility
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with a higher scheduling prority.
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.Pp
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Some shells may provide a builtin
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.Nm
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@ -79,32 +65,32 @@ Consult the
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.Xr builtin 1
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manual page.
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.Sh EXAMPLES
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$ nice -5 date
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$ nice -n 5 date
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.Pp
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Execute command
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Execute utility
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.Sq date
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at priority 5 assuming the priority of the
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shell is 0.
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.Pp
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# nice -16 nice --35 date
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# nice -n 16 nice -n -35 date
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.Pp
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Execute command
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Execute utility
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.Sq date
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at priority -19 assuming the priority of the
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shell is 0 and you are the super-user.
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.Sh DIAGNOSTICS
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If
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.Ar command
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.Ar utility
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is invoked, the exit status of
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.Nm
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is the exit status of
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.Ar command .
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.Ar utility .
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.Pp
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An exit status of 126 indicates
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.Ar command
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.Ar utility
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was found, but could not be executed.
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An exit status of 127 indicates
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.Ar command
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.Ar utility
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could not be found.
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.Sh SEE ALSO
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.Xr builtin 1 ,
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@ -114,8 +100,17 @@ could not be found.
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.Xr getpriority 2 ,
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.Xr setpriority 2 ,
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.Xr renice 8
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.Sh COMPATIBILITY
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The traditional
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.Fl Ns Ar increment
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option has been deprecated but is still supported.
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.Sh STANDARDS
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The
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.Nm
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utility conforms to
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.St -p1003.1-2001 .
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.Sh HISTORY
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A
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.Nm
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command appeared in
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utility appeared in
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.At v6 .
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@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$");
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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@ -67,35 +68,49 @@ main(argc, argv)
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int argc;
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char *argv[];
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{
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int niceness = DEFNICE;
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long niceness = DEFNICE;
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int ch;
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char *ep;
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if (argc < 2)
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usage();
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/* Obsolescent syntax: -number, --number */
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if (argc >= 2 && argv[1][0] == '-' && (argv[1][1] == '-' ||
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isdigit((unsigned char)argv[1][1])) && strcmp(argv[1], "--") != 0)
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if (asprintf(&argv[1], "-n%s", argv[1] + 1) < 0)
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err(1, "asprintf");
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if (argv[1][0] == '-') {
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if (argv[1][1] == '-' || isdigit(argv[1][1])) {
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niceness = atoi(argv[1] + 1);
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++argv;
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} else
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errx(1, "illegal option -- %s", argv[1]);
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while ((ch = getopt(argc, argv, "n:")) != -1) {
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switch (ch) {
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case 'n':
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errno = 0;
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niceness = strtol(optarg, &ep, 10);
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if (ep == optarg || *ep != '\0' || errno ||
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niceness < INT_MIN || niceness > INT_MAX)
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errx(1, "%s: invalid nice value", optarg);
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break;
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default:
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usage();
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}
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}
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argc -= optind;
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argv += optind;
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if (argv[1] == NULL)
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if (argc == 0)
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usage();
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errno = 0;
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niceness += getpriority(PRIO_PROCESS, 0);
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if (errno)
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err(1, "getpriority");
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if (setpriority(PRIO_PROCESS, 0, niceness))
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if (setpriority(PRIO_PROCESS, 0, (int)niceness))
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err(1, "setpriority");
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execvp(argv[1], &argv[1]);
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err(errno == ENOENT ? 127 : 126, "%s", argv[1]);
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execvp(*argv, argv);
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err(errno == ENOENT ? 127 : 126, "%s", *argv);
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}
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void
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usage()
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{
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(void)fprintf(stderr, "usage: nice [-number] command [arguments]\n");
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(void)fprintf(stderr, "usage: nice [-n incr] utility [arguments]\n");
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exit(1);
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}
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