# Key search in files

**URL:** <https://www.ruby-forum.com/t/key-search-in-files/187978>\
**Category:** Ruby\
**Created:** [May 3, 2010, 6:08pm UTC](https://www.ruby-forum.com/t/key-search-in-files/187978 "2010-05-03T18:08:31Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![quantum17](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/q/db5fbb/32.png) [@quantum17](https://www.ruby-forum.com/u/quantum17)\
**Post date:** [May 3, 2010, 6:08pm UTC](https://www.ruby-forum.com/t/key-search-in-files/187978/1 "2010-05-03T18:08:31Z")

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i am trying to find a set of keys within specific files under a specific  
directory. i read the keys from a file and iterate through them opening  
and looking all the files under the specified directory. However only  
the last key seems to be found in the files…

srcFiles = Dir.glob(File.join("\*\*", “\*.txt”))  
keys = File.readlines(“sp.txt”)

keys.each{ |key|  
srcFiles.each{|src|  
linenumber = 0  
File.readlines(src).each{ |line|  
linenumber += 1  
if line.include? key then  
puts “found #{key}”  
}  
}  
}

---

<div class="post-metadata">

**Author:** ![quantum17](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/q/db5fbb/32.png) [@quantum17](https://www.ruby-forum.com/u/quantum17)\
**Post date:** [May 4, 2010, 9:30am UTC](https://www.ruby-forum.com/t/key-search-in-files/187978/2 "2010-05-04T09:30:30Z")

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2010/5/3 Qnmt M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> linenumber = 0  
> File.readlines(src).each{ |line|  
> linenumber += 1  
> if line.include? key then  
> puts “found #{key}”  
> }  
> }  
> }

This is likely caused by the fact, that you do not postprocess what  
you get from File.readlines:

$ echo 111 \>| x  
$ echo 222 \>\> x  
$ ruby19 -e ‘p File.readlines(“x”)’  
[“111\n”, “222\n”]  
$

Note the trailing line delimiter.

Also, your approach is very inefficient: you open and read every file

# of keys times. You better exchange outer and inner loop and open

each file only once while searching for all keys in one line.

Btw, what you attempt to do can be done by GNU find and fgrep already:

$ find . -type f -name ‘\*.txt’ -print0 | xargs -r0 fgrep -f sp.txt

Or, with a shell that knows “\*\*” expansion, e.g. zsh

$ fgrep -f sp.txt \*\*/\*.txt

If you are only interested in file names you can add option -l to fgrep.

Kind regards

robert

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<div class="post-metadata">

**Author:** ![quantum17](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/q/db5fbb/32.png) [@quantum17](https://www.ruby-forum.com/u/quantum17)\
**Post date:** [May 4, 2010, 10:23am UTC](https://www.ruby-forum.com/t/key-search-in-files/187978/3 "2010-05-04T10:23:12Z")

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thanks for your reply and advices robert.

the problem was really about postprocessing the result of File.readlines  
and your idea about switching the loop order significantly improved the  
performance.

about doing the same thing with GNU commands, i wrote this for windows  
environment and not sure if it has such a command utility

cem