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Full Discussion: What does shell check
Homework and Emergencies Homework & Coursework Questions What does shell check Post 302477527 by jim mcnamara on Sunday 5th of December 2010 04:32:13 PM
Old 12-05-2010
Do you have a textbook? Almost all of the books I taught out of years ago went in to this explicitly.

What the question is asking: how does a POSIX shell locate a command.

This location "engine" is what the "which" unix command uses. It tells you what type of command : builtin (do you know what that means?), alias (again do you know?), and file (like /usr/bin/ping).

So you need to know what those terms are. Finally look up the PATH variable - it handles the last item in the list: locating command files like /usr/bin/ping. Almost all of the answer is in the reponse, I gave. You need to read a bit and put the pieces together.

If you are going to use UNIX for anything useful, my simply giving you the answer for this would be terrible for you. The above concept is REALLY important, and is the cause of lots of confusion for people who do not know.

If you don't have a text book, I can refer you to some internet pages.
 

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LEARN ABOUT OSF1

tcl

tcl(1)							      General Commands Manual							    tcl(1)

NAME

       tcl, tk, tcl-tk - Tool Command Language

DESCRIPTION

       The  tcl  software  is  unsupported software that is provided as part of Tru64 UNIX.  Compaq will fix problems in this unsupported software
       only if they are specific to Tru64 UNIX.  Compaq will not fix problems that are integral to the software itself or that occur when the com-
       ponent is used on UNIX systems other than Tru64 UNIX.  Compaq will not add functionality to this software.

       Except  for  this reference page, other reference pages that Tru64 UNIX supplies for tcl are passed through without changes.  The reference
       pages distributed as part of this software are available in the directories  /usr/share/doclib/annex/man/man[1-9].   You  should  use  this
       directory stem in the man command or add it to the MANPATH environment variable to make these files available to the man command.

									  Note

       Compaq  is  not	responsible  for the content or quality of reference pages and other documents installed under the /usr/share/doclib/annex
       directory  and  does  not  revise  this	material  in  response	to  customer  problem  reports.  Reference  pages  installed   under   the
       /usr/share/doclib/annex/man directory are not available from Compaq in book form; for example, they are not included in the reference manu-
       als that you receive when you order the Tru64 UNIX documentation set as hard copy books.

       Problems related to the content or quality of any documentation installed in the /usr/share/doclib/annex directory tree should be  sent	to
       the developers of the documentation.

       The format for changing the search path with the man command is: man -P /usr/share/doclib/annex/man [section] title...

       If  you	are  using  the  Bourne,  Korn,  or  POSIX  shells,  use  the following command sequence to modify your environment: MANPATH=$MAN-
       PATH:/usr/share/doclib/annex/man export MANPATH

       If you are using the C shell, enter the command: setenv MANPATH `echo $MANPATH`:/usr/share/doclib/annex/man

       See the reference pages for the man(1) command for additional information on the search path used to locate files.

       The reference pages associated with this product are not included in the whatis data base created by the catman	command.   Therefore,  the
       man -k and apropos commands will not locate reference pages included with this product.

SEE ALSO

       Commands:  apropos(1), catman(8), man(1)

																	    tcl(1)
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