1SH(1) General Commands Manual SH(1)
2
6 sh, for, case, if, while, :, ., break, continue, cd, eval, exec, exit,
7 export, login, read, readonly, set, shift, times, trap, umask, wait -
8 command language
9
11 sh [ -ceiknrstuvx ] [ arg ] ...
12
14 Sh is a command programming language that executes commands read from a
15 terminal or a file. See invocation for the meaning of arguments to the
16 shell.
17 Commands.
19 A simple-command is a sequence of non blank words separated by blanks
20 (a blank is a tab or a space). The first word specifies the name of
21 the command to be executed. Except as specified below the remaining
22 words are passed as arguments to the invoked command. The command name
23 is passed as argument 0 (see execve(2)). The value of a simple-command
24 is its exit status if it terminates normally or 200+status if it termi‐
25 nates abnormally (see sigvec(2) for a list of status values).
26 A pipeline is a sequence of one or more commands separated by |. The
28 standard output of each command but the last is connected by a pipe(2)
29 to the standard input of the next command. Each command is run as a
30 separate process; the shell waits for the last command to terminate.
31 A list is a sequence of one or more pipelines separated by ;, &, && or
33 || and optionally terminated by ; or &. ; and & have equal precedence
34 which is lower than that of && and ||, && and || also have equal prece‐
35 dence. A semicolon causes sequential execution; an ampersand causes
36 the preceding pipeline to be executed without waiting for it to finish.
37 The symbol && (||) causes the list following to be executed only if the
38 preceding pipeline returns a zero (non zero) value. Newlines may
39 appear in a list, instead of semicolons, to delimit commands.
40 A command is either a simple-command or one of the following. The
42 value returned by a command is that of the last simple-command executed
43 in the command.
44 for name [in word ...] do list done
46 Each time a for command is executed name is set to the next word
47 in the for word list. If in word ... is omitted, in "$@" is
48 assumed. Execution ends when there are no more words in the
49 list.
50 case word in [pattern [ | pattern ] ... ) list ;;] ... esac
52 A case command executes the list associated with the first pat‐
53 tern that matches word. The form of the patterns is the same as
54 that used for file name generation.
55 if list then list [elif list then list] ... [else list] fi
57 The list following if is executed and if it returns zero the
58 list following then is executed. Otherwise, the list following
59