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Full Discussion: Help with understanding of alias
Top Forums Shell Programming and Scripting Help with understanding of alias Post 302634821 by Roy987 on Thursday 3rd of May 2012 11:23:25 PM
Old 05-04-2012
Help with understanding of alias
Hi, I saw the following explanation about alias in bash from gnu website, but I didn't get the meaning:
Bash always reads at least one complete line of input before executing any of the commands on that line.
Aliases are expanded when a command is read, not when it is executed. Therefore, an alias definition
appearing on the same line as another command does not take effect until the next line of input is read. The
commands following the alias definition on that line are not affected by the new alias. This behavior is also an
issue when functions are executed. Aliases are expanded when a function definition is read, not when the
function is executed, because a function definition is itself a compound command. As a consequence, aliases
defined in a function are not available until after that function is executed. To be safe, always put alias
definitions on a separate line, and do not use alias in compound commands.

especially the part related with function, can anybody help explain in short sentences cause I am not a English speaker.
Great Thanks.
Roy987
 

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LEARN ABOUT SUSE

aliasadm

aliasadm(1M)                                              System Administration Commands                                              aliasadm(1M)

NAME

       aliasadm - manipulate the NIS+ aliases map

SYNOPSIS

       aliasadm -a alias expansion [options comments] optional flags

       aliasadm -c alias expansion [ options comments] [ optional flags]

       aliasadm -d alias [ optional flags]

       aliasadm -e alias [ optional flags]

       aliasadm -l alias [ optional flags]

       aliasadm -m alias [ optional flags]

       aliasadm [-I] [-D domainname] [-f filename] [-M mapname]

DESCRIPTION

       aliasadm makes changes to the alias map.

       The alias map is an NIS+ table object with four columns:

       alias           The name of the alias as a null terminated string.

       expansion       The value of the alias as it would appear in a sendmail /etc/aliases file.

       options         A  list  of options applicable to this alias.  The only option currently supported is  CANON. With this option, if the user
                       has requested an inverse alias lookup, and there is more than one alias with this expansion, this alias  is  given  prefer-
                       ence.

       comments        An  arbitrary  string  containing comments about this alias. The sendmail(1M) command reads this map in addition to the NIS
                       aliases map and the local  /etc/aliases database.

OPTIONS

       -a              Add an alias.

       -c              Change an alias.

       -d              Delete an alias.

       -e              Edit the alias map.

       -I              Initialize the NIS+ aliases database.

       -l              List the alias map.

       -m              Print or match an alias.

       -D domainname   Edit the map in domain  domainname instead of the current domain.

       -f filename     When editing or listing the database, use filename instead of invoking the editor.

       -M mapname      Edit mapname instead of mail_aliases.

FILES

       /etc/aliases    mail aliases for the local host in ASCII format

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWnisu                     |
       +-----------------------------+-----------------------------+

SEE ALSO

       sendmail(1M), attributes(5)

NOTES

       NIS+ might not be supported in future releases of the SolarisTM Operating Environment. Tools to aid the migration from  NIS+  to  LDAP  are
       available in the Solaris 9 operating environment. For more information, visit http://www.sun.com/directory/nisplus/transition.html.

SunOS 5.10                                                          12 Dec 2001                                                       aliasadm(1M)
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