User Commands alias(1)
NAME
alias, unalias - create or remove a pseudonym or shorthand
for a command or series of commands
SYNOPSIS
/usr/bin/alias [alias-name[= string...]
/usr/bin/unalias alias-name...
/usr/bin/unalias -a
csh
alias [name [def]
unalias pattern
ksh
alias [-tx] [name[= value]...]
unalias name...
unalias [-a]
ksh93
alias [-ptx] [name[= value]...]
unalias [-a] [name...]
DESCRIPTION
The alias and unalias utilities create or remove a pseudonym
or shorthand term for a command or series of commands, with
different functionality in the C-shell and Korn shell
environments.
/usr/bin/alias
The alias utility creates or redefines alias definitions or
writes the values of existing alias definitions to standard
output. An alias definition provides a string value that
replaces a command name when it is encountered.
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User Commands alias(1)
An alias definition affects the current shell execution
environment and the execution environments of the subshells
of the current shell. When used as specified by this docu-
ment, the alias definition does not affect the parent pro-
cess of the current shell nor any utility environment
invoked by the shell.
/usr/bin/unalias
The unalias utility removes the definition for each alias
name specified. The aliases are removed from the current
shell execution environment. The -a option removes all alias
definitions from the current execution environment.
csh
alias assigns def to the alias name. The assigned def is a
list of words that can contain escaped history-substitution
metasyntax. name is not allowed to be alias or unalias. If
def is omitted, the alias name is displayed along with its
current definition. If both name and def are omitted, all
aliases are displayed.
Because of implementation restrictions, an alias definition
must have been entered on a previous command line before it
can be used.
unalias discards aliases that match (filename substitution)
pattern. All aliases can be removed by `unalias *'.
ksh
alias with no arguments prints the list of aliases in the
form name=value on standard output. An alias is defined for
each name whose value is specified. A trailing space in
value causes the next word to be checked for alias substitu-
tion. The -t flag is used to set and list tracked aliases.
The value of a tracked alias is the full pathname
corresponding to the specified name. The value becomes unde-
fined when the value of PATH is reset but the aliases
remained tracked. Without the -t flag, for each name in the
argument list for which no value is specified, the name and
value of the alias is printed. The -x flag is used to set or
print exported aliases. An exported alias is defined for
scripts invoked by name. The exit status is non-zero if a
name is specified, but no value, and no alias has been
defined for the name.
The aliass specified by the list of names can be removed
from the alias list with unalias.
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User Commands alias(1)
ksh93
alias creates or redefines alias definitions or writes the
existing alias definitions to standard output.
An alias definition provides a string value that replaces a
command name when the command is read. Alias names can con-
tain any printable character that is not special to the
shell. If an alias value ends in a SPACE or TAB, the word
following the command name the alias replaces is also
checked to see whether it is an alias.
If no names are specified, the names and values of all
aliases are written to standard output. Otherwise, for each
name that is specified, and =value is not specified, the
current value of the alias corresponding to name is written
to standard output. If =value is specified, the alias name
is created or redefined.
alias is built-in to the shell as a declaration command so
that field splitting and pathname expansion are not per-
formed on the arguments. Tilde expansion occurs on value. An
alias definition only affects scripts read by the current
shell environment. It does not affect scripts run by this
shell.
unalias removes the definition of each named alias from the
current shell execution environment, or all aliases if -a is
specified. It does not affect any commands that have already
been read and subsequently executed.
OPTIONS
The following option is supported by unalias:
-a Removes all alias definitions from the current shell
execution environment.
ksh
The following option is supported by alias:
-t Sets and lists tracked aliases.
ksh93
The following options are supported by alias:
-p Causes the output to be in the form of alias commands
that can be used as input to the shell to recreate the
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User Commands alias(1)
current aliases.
-t Specifies tracked aliases.
Tracked aliases connect a command name to the
command's pathname, and are reset when the PATH vari-
able is unset. The tracked aliases feature is now
obsolete.
-x Ignored, this option is obsolete.
The following option is supported by unalias:
-a Causes all alias definitions to be removed. name
operands are optional and ignored if specified.
OPERANDS
The following operands are supported:
alias
alias-name Write the alias definition to standard output.
unalias
alias-name The name of an alias to be removed.
alias-name=string Assign the value of string to the alias
alias-name.
If no operands are specified, all alias definitions are
written to standard output.
OUTPUT
The format for displaying aliases (when no operands or only
name operands are specified) is:
"%s=%s\n" name, value
The value string is written with appropriate quoting so that
it is suitable for reinput to the shell.
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User Commands alias(1)
EXAMPLES
Example 1 Modifying a Command's Output
This example specifies that the output of the ls utility is
columnated and more annotated:
example% alias ls="ls -CF"
Example 2 Repeating Previous Entries in the Command History
File
This example creates a simple "redo" command to repeat pre-
vious entries in the command history file:
example% alias r='fc -s'
Example 3 Specifying a Command's Output Options
This example provides that the du utility summarize disk
output in units of 1024 bytes:
example% alias du=du -k
Example 4 Dealing with an Argument That is an Alias Name
This example sets up the nohup utility so that it can deal
with an argument that is an alias name:
example% alias nohup="nohup "
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of alias and unalias:
LANG, LCAL, LCTYPE, LCMESAGES, and NLSPATH.
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EXIT STATUS
The following exit values are returned:
0 Successful completion.
alias
>0 One of the alias-name operands specified did not have
an alias definition, or an error occurred.
unalias
>0 One of the alias-name operands specified did not
represent a valid alias definition, or an error
occurred.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
csh, ksh
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
Interface Stability Committed
Standard See standards(5).
ksh93
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
Interface Stability Uncommitted
SEE ALSO
csh(1), ksh(1), ksh93(1), shellbuiltins(1), attributes(5),
environ(5), standards(5)
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