[techtalk] Re: [ILUG] How a script is called

[Caolan McNamara]

At 08:15 16.08.00 +0100, Conor Daly wrote:
>Anyone know how a bash / csh script can tell if it was called in a pipeline or
>directly from the commandline?  I've a script that I want to run either by
>catting a file through a pipe or by invoking from the commandline with the
>file as an arg and I need the script to behave slightly differently in either
>case.

Just check to see if there are any command line arguments which pertain to an
input file. If there's none assume that we're a pipe, that's pretty much 
all that
existing apps do.

A dumbo script which optionally takes a single argument which is an input file,
with no argument its a pipe

#!/bin/sh
#count command-line arguments
if [ $# = 0 ]; then
         a pipe
else
         not a pipe
fi

C.
--
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