diff options
Diffstat (limited to 'bin/sh/sh.1')
| -rw-r--r-- | bin/sh/sh.1 | 46 |
1 files changed, 34 insertions, 12 deletions
diff --git a/bin/sh/sh.1 b/bin/sh/sh.1 index 1c3f8fb..fa68720 100644 --- a/bin/sh/sh.1 +++ b/bin/sh/sh.1 @@ -32,7 +32,7 @@ .\" from: @(#)sh.1 8.6 (Berkeley) 5/4/95 .\" $FreeBSD$ .\" -.Dd January 26, 2014 +.Dd November 14, 2014 .Dt SH 1 .Os .Sh NAME @@ -259,6 +259,12 @@ from input when in interactive mode. Force the shell to behave interactively. .It Fl m Li monitor Turn on job control (set automatically when interactive). +A new process group is created for each pipeline (called a job). +It is possible to suspend jobs or to have them run in the foreground or +in the background. +In a non-interactive shell, +this option can be set even if no terminal is available +and is useful to place processes in separate process groups. .It Fl n Li noexec If not interactive, read commands but do not execute them. @@ -584,7 +590,8 @@ the following actions: Leading words of the form .Dq Li name=value are stripped off and assigned to the environment of -the simple command. +the simple command +(they do not affect expansions). Redirection operators and their arguments (as described below) are stripped off and saved for processing. @@ -788,10 +795,13 @@ should indicate the various exit codes and what they mean. Additionally, the built-in commands return exit codes, as does an executed shell function. .Pp -If a command is terminated by a signal, its exit status is 128 plus -the signal number. -Signal numbers are defined in the header file -.In sys/signal.h . +If a command is terminated by a signal, its exit status is greater than 128. +The signal name can be found by passing the exit status to +.Li kill -l . +.Pp +If there is no command word, +the exit status is the exit status of the last command substitution executed, +or zero if the command does not contain any command substitutions. .Ss Complex Commands Complex commands are combinations of simple commands with control operators or keywords, together creating a larger complex @@ -811,7 +821,8 @@ function definition .El .Pp Unless otherwise stated, the exit status of a command is -that of the last simple command executed by the command. +that of the last simple command executed by the command, +or zero if no simple command was executed. .Ss Pipelines A pipeline is a sequence of one or more commands separated by the control operator @@ -895,6 +906,8 @@ The format for running a command in background is: If the shell is not interactive, the standard input of an asynchronous command is set to .Pa /dev/null . +.Pp +The exit status is zero. .Ss Lists (Generally Speaking) A list is a sequence of zero or more commands separated by newlines, semicolons, or ampersands, @@ -933,6 +946,13 @@ command is: .Ic fi .Ed .Pp +The exit status is that of selected +.Ic then +or +.Ic else +list, +or zero if no list was selected. +.Pp The syntax of the .Ic while command is: @@ -953,6 +973,9 @@ in place of which causes it to repeat until the exit status of the first list is zero. .Pp +The exit status is that of the last execution of the second list, +or zero if it was never executed. +.Pp The syntax of the .Ic for command is: @@ -1033,10 +1056,6 @@ continuing until a list terminated with or the end of the .Ic case command. -The exit code of the -.Ic case -command is the exit code of the last command executed in the list or -zero if no patterns were matched. .Ss Grouping Commands Together Commands may be grouped by writing either .Pp @@ -1124,6 +1143,8 @@ and the syntax is: The .Ic local command is implemented as a built-in command. +The exit status is zero +unless the command is not in a function or a variable name is invalid. .Pp When a variable is made local, it inherits the initial value and exported and readonly flags from the variable @@ -2515,7 +2536,8 @@ and so on, decreasing the value of .Li $# by one. -If there are zero positional parameters, shifting does not do anything. +For portability, shifting if there are zero positional parameters +should be avoided, since the shell may abort. .It Ic test A built-in equivalent of .Xr test 1 . |
