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Full Discussion: Executing multiple child scripts - failing
Top Forums Shell Programming and Scripting Executing multiple child scripts - failing Post 302987307 by bakunin on Thursday 8th of December 2016 05:52:02 AM
Old 12-08-2016
+1 @RudiC!

When i write complex processing scripts where all sorts of things could go wrong i usually do it this way:

First, a list of commands that have to be executed (in case everything works perfectly). Let us say the list is:

Code:
cmd1 -a -b
cmd2 /bla/foo/bar
cmd3

Then i write the script like this:

Code:
if ! cmd1 -a -b ; then
     echo "Error executing cmd1 -a -b" >2&
     exit 3
fi

if ! cmd2 /bla/foo/bar ; then
     echo "Error executing cmd2 /bla/foo/bar" >2&
     exit 2
fi

if ! cmd3 ; then
     echo "Error executing cmd3"  >2&
     exit 1
fi

exit 0

Notice that the script will exit with a different error code depending on which command the script fails. Also notice that convention in UNIX is that a RC of 0 means "success" and everything else means varying reasons of failure. This is why the fi-construct (usually) works: a command succeeding in what it is suppsed to do will return 0 and therefore if ! cmd... will evaluate to false whereas a command not succeeding will return non-0 and if ! cmd... will return true triggering the then..fi.

I hope this helps.

bakunin
 

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LEARN ABOUT DEBIAN

source

source(3tcl)						       Tcl Built-In Commands						      source(3tcl)

__________________________________________________________________________________________________________________________________________________

NAME

       source - Evaluate a file or resource as a Tcl script

SYNOPSIS

       source fileName

       source -encoding encodingName fileName													   |
_________________________________________________________________

DESCRIPTION

       This  command takes the contents of the specified file or resource and passes it to the Tcl interpreter as a text script.  The return value
       from source is the return value of the last command executed in the script.  If an error occurs in evaluating the contents  of  the  script
       then  the source command will return that error.  If a return command is invoked from within the script then the remainder of the file will
       be skipped and the source command will return normally with the result from the return command.

       The end-of-file character for files is "32" (^Z) for all platforms.  The source command will  read  files  up  to  this  character.   This
       restriction  does  not  exist for the read or gets commands, allowing for files containing code and data segments (scripted documents).	If
       you require a "^Z" in code for string comparison, you can use "32" or "u001a", which will be safely substituted by the  Tcl  interpreter
       into "^Z".

       The  -encoding  option  is  used  to specify the encoding of the data stored in fileName.  When the -encoding option is omitted, the system |
       encoding is assumed.

EXAMPLE

       Run the script in the file foo.tcl and then the script in the file bar.tcl:
	      source foo.tcl
	      source bar.tcl
       Alternatively:
	      foreach scriptFile {foo.tcl bar.tcl} {
		 source $scriptFile
	      }

SEE ALSO

       file(3tcl), cd(3tcl), encoding(3tcl), info(3tcl)

KEYWORDS

       file, script

Tcl																      source(3tcl)
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