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Full Discussion: Speeding up a Shell Script (find, grep and a for loop)
Top Forums UNIX for Dummies Questions & Answers Speeding up a Shell Script (find, grep and a for loop) Post 302221796 by Dave Stockdale on Tuesday 5th of August 2008 08:05:41 AM
Old 08-05-2008
Speeding up a Shell Script (find, grep and a for loop)
Hi all,

I'm having some trouble with a shell script that I have put together to search our web pages for links to PDFs.

The first thing I did was:

Code:
ls -R | grep .pdf > /tmp/dave_pdfs.out

Which generates a list of all of the PDFs on the server. For the sake of arguement, say it looks like this:

file1.pdf
file2.pdf
file3.pdf
file4.pdf

I then put this info into an array in a shell script, and loop through the array, searching all .htm and .html files in the site
for the value:

Code:
# The Array
pdfs=("file1.pdf" "file2.pdf" "file3.pdf" "file4.pdf")

# Just a counter that gets incremented for each iteration
counter=1

# For every value in the array
for value in ${pdfs[@]}
do

# Tell the user which file is being searched for, and how far along in the overall process we are.
echo "Working on $value..."
echo "($counter of ${#pdfs[*]})"

# Add what is being searched for to the output file
echo "$value is linked to from" >> /tmp/dave_locations.out

# Find all .htm and .html files with the filename we are looking for in, and add it to the output file
find . -name "*.htm*" -exec grep -l $value {} \; >> /tmp/dave_locations.out

# Adding a space afterwards
echo " " >> /tmp/dave_locations.out

# Increment the counter.
counter=`expr $counter + 1`

done

This does work.

However, our site is huge (1491 PDFs, and a whole lot of .htm and .html pages). Each iteration through the loop
takes around about 55 seconds. I've calculated that this shell script will take 6 days to complete.

Does anyone please know of a better (and significantly faster) way of doing this?

Any help would be greatly appreciated. I'm a bit of a unix newbie, and it took me hours just to get this far.
 

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LEARN ABOUT CENTOS

pdfseparate

pdfseparate(1)						      General Commands Manual						    pdfseparate(1)

NAME

       pdfseparate - Portable Document Format (PDF) page extractor

SYNOPSIS

       pdfseparate [options] PDF-file PDF-page-pattern

DESCRIPTION

       pdfseparate extract single pages from a Portable Document Format (PDF).

       pdfseparate  reads  the PDF file PDF-file, extracts one or more pages, and writes one PDF file for each page to PDF-page-pattern, PDF-page-
       pattern should contain %d.  %d is replaced by the page number.

       The PDF-file should not be encrypted.

OPTIONS

       -f number
	      Specifies the first page to extract. If -f is omitted, extraction starts with page 1.

       -l number
	      Specifies the last page to extract. If -l is omitted, extraction ends with the last page.

       -v     Print copyright and version information.

       -h     Print usage information.	(-help and --help are equivalent.)

EXAMPLE

       pdfseparate sample.pdf sample-%d.pdf

       extracts all pages from sample.pdf, if i.e. sample.pdf has 3 pages, it produces

       sample-1.pdf, sample-2.pdf, sample-3.pdf

AUTHOR

       The pdfseparate software and documentation are copyright 1996-2004 Glyph & Cog, LLC  and  copyright  2005-2011  The  Poppler  Developers  -
       http://poppler.freedesktop.org

SEE ALSO

       pdfunite(1),

								 15 September 2011						    pdfseparate(1)
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