Unix Tip: OPERATING ON MULTIPLE FILES

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3613 - December 31, 2013

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@virtualipgroup.com



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