sh-posix.1 (2010 09)

s
sh-posix(1) sh-posix(1)
-c The number of 512-byte blocks in the size of core dumps.
-d The number of kilobytes in the size of the data area.
-f The number of 512-byte blocks in files written by child processes (files of any size can be read).
-n The number of file descriptors.
-s The number of kilobytes in the size of the stack area.
-t The number of seconds to be used by each process.
umask [-S][mask]
Set the user file-creation mask mask . mask can be either an octal number or a symbolic value as
described in umask(1). A symbolic value shows permissions that are unmasked. An octal value
shows permissions that are masked off.
Without mask, print the current value of the mask. With
-S, print the value in symbolic format.
Without
-S, print the value as an octal number. The output from either form can be used as the
mask of a subsequent invocation of umask.
unalias name ...
unalias -a
Remove each name from the alias list. With
-a, remove all alias definitions from the current
shell execution environment. See also the
alias
special command.
%
unset [-fv] name ...
Remove the named shell parameters from the parameter list. Their values and attributes are
erased. Read-only variables cannot be unset. With -f, names refer to function names. With
-v,
names refer to variable names. Unsetting
_, ERRNO, LINENO, MAILCHECK, OPTARG
, OPTIND,
RANDOM, SECONDS, and TMOUT removes their special meaning, even if they are subsequently
assigned to.
wait [job]
Wait for the specified job to terminate or stop, and report its status. This status becomes the return
code for the wait command. Without job , wait for all currently active child processes to terminate
and returns with a zero exit status. See the Jobs subsection for a description of the format of job.
whence [-pv] name ...
For each name , indicate how it would be interpreted if used as a command name. With
-v, produce
a more verbose report. With
-p do a path search for name, disregarding any use as an alias, a
function, or a reserved word.
Comments
A word beginning with
# causes that word and all the following characters up to a newline to be ignored.
Aliasing
The first word of each command is replaced by the text of an
alias,ifan
alias for this word has been
defined. An
alias name consists of any number of characters excluding metacharacters, quoting char-
acters, file expansion characters, parameter and command substitution characters, and =. The replace-
ment string can contain any valid shell script, including the metacharacters listed above. The first word
of each command in the replaced text, other than any that are in the process of being replaced, will be
tested for additional aliases. If the last character of the alias value is a blank, the word following the
alias is also checked for alias substitution. Aliases can be used to redefine special commands, but cannot
be used to redefine the keywords listed in the Compound Commands subsection. Aliases can be created,
listed, and exported with the alias command and can be removed with the unalias command.
Exported aliases remain in effect for subshells but must be reinitialized for separate invocations of the
shell (see the Shell Invocation subsection).
Aliasing is performed when scripts are read, not while they are executed. Therefore, for it to take effect,
an
alias must be executed before the command referring to the alias is read.
Aliases are frequently used as a shorthand for full path names. An option to the aliasing facility allows
the value of the alias to be automatically set to the full path name of the corresponding command. These
aliases are called tracked aliases. The value of a tracked alias is defined the first time the identifier is
read and becomes undefined each time the
PATH variable is reset. These aliases remain tracked so that
the next reference will redefine the value. Several tracked aliases are compiled into the shell. The -h
option of the set command converts each command name that is an identifier into a tracked alias.
The following exported aliases are compiled into the shell but can be unset or redefined:
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