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Re: alias vs unalias

From: Chet Ramey
Subject: Re: alias vs unalias
Date: Tue, 17 Dec 2002 09:00:21 -0500

> I have found a difference in the handling of "alias" vs "unalias" and believe 
> this
> is a bug (if it isn't, would someone please mail me as to why). Here's my 
> finding:

Doesn't anyone read the documentation anymore?  From bash.1:

       The rules concerning the definition and use of aliases are
       somewhat  confusing.   Bash always reads at least one com-
       plete 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  defi-
       nition  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.

``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet )

Chet Ramey, ITS, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/

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