[olug] Unix Tip: OPERATING ON MULTIPLE FILES

[Unix Guru Universe]

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			      UNIX GURU UNIVERSE 
			         UNIX HOT TIP

			Unix Tip 1876 - February 19, 2003

		    http://www.ugu.com/sui/ugu/show?tip.today

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OPERATING ON MULTIPLE FILES

Have you ever felt the need to perform a 
set of operations on multiple files 
simultaneously???

Here is a solution for that.

For instance, if it is required to perform 
multiple operations like searching a string 
(using grep), and executing an awk or perl
script etc, etc. on not just one file but a 
set of files, use the following commands at 
the unix prompt:

 $<: foreach i (<file_list>)
 ? echo $i
 ? grep <search_pattern> $i > tmp
 ? awk -f awk_script tmp >> report
 ? ....
 ? ....
 ? end
$<:

The files list in the brackets can be either

* Specifically mentioned

* A unix variable which contains a list of 
file names.  For instance, the variable 
"p" can be assigned all the files starting 
with string "data" as follows:
    set p = (data*)
Other examples are:
    set g = `grep -l "Startpoint" * `
or 
    set all = * 
(This assigns all file names in the current 
directory to the variable "all" )

And its usage with the "foreach" command will 
be as follows:
       
$<:  foreach i ($all)
   .....
   .....
end

This tip generously supported by: lakshmi at virtualipgroup.com



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