'''[http://tiswww.case.edu/php/chet/bash/bashtop.html%|%bash]''' is [Unix
shells%|%Unix shell] in the [Bourne shell] family.  The name is an acronym for ''Bourne-Again SHell'', which is a slight pun on the old Bourne shell '''sh'''.



** Attributes **

   website:   http://tiswww.case.edu/php/chet/bash/bashtop.html

   website:   http://www.gnu.org/software/bash/



** Reference **

   [http://www.gnu.org/software/bash/manual/bash.html%|%official reference]:   

   [http://tiswww.case.edu/php/chet/bash/FAQ%|%Bash FAQ]:   the official FAQ

   [http://www.tldp.org/LDP/abs/html/%|%Advanced Bash Scripting Guide], by Mendel Cooper:   An in-depth exploration of the art of shell scripting

   [http://mywiki.wooledge.org/BashFAQ%|%Bash FAQ]:   by denizens of the freenode #bash channel

   [http://mywiki.wooledge.org/BashPitfalls%|%Bash Pitfals]:   also by the freenode #bash channel crowd



** Description **

There seems to be no [Tcl Heritage] directly linked to '''bash''' (at least not yet),
but the languages are similar in many ways.
The quoting scheme used in Tcl was (almost certainly) influenced by shell languages such as Bash.

Programmers in Tcl have been confused at times by the Tcl quoting scheme
because they expected Tcl quoting to operate the same way as Bash or other shell-language quoting,
so many Tcl programmers would probably do well to know
the pitfalls and frequently asked questions about Bash.
Also, Bash commands can be invoked through Tcl via [exec] and friends,
in which case it will probably help to be familiar with the differences.
In particular, Bash tends to automatically expand [wild cards] such as '''*.txt''',
whereas in Tcl such expansions will typically require an explicit [glob] command.




** Bug: syntax error near unexpected token **

With newer version of Bash, (3.0 and up), When building older Tcl versions or Tcl extensions based on [TEA] ./[configure] might fail with an error resembling:

======none
./configure: line 7624: syntax error near unexpected token `)'
======

The cause of this error is a typo in tcl.m4 and the generated configure file. Previous versions of bash accepted the incorrectly quoted version, but newer versions will error out. The solution is to create a new configure file with the correct quoting:

======none
cp configure{,.orig} && sed "s/relid'/relid/" configure.orig > configure
======

The typo has been fixed from Tcl 8.4.14. Extensions might exhibit this problem for quite some time to come.



** The Joy of Bash **

   [http://lists.gnu.org/archive/html/bug-bash/2009-05/msg00017.html%|%Feature Request: export extglob from environment]:   for a good time, take the ability to export functions via environment variables, sprinkle in shell settings that change the syntax of function definitions, and then try to run other executable bash scripts that aren't expecting that syntax.   Or just preserve your sanity by using Tcl instead.



** See Also **

   [Playing Bourne shell]:   ways to port bash scripts to Tcl.


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