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Exploring Linux Part 23
by Alan German
For me, one
of the great mysteries in Linux has always been how to
find specific files within the overall file system. I
consider myself to be reasonably well organized in terms
of file storage so I have never really had to delve into
the various file search commands that Linux has to offer.
But, recently, I came across a blog entry discussing how
to use the locate command to search for files
(http://linuxaria.com/howto/find-files-on-linux-with-the-command-locate). It turns out that locate needs
an updated database of file names in order to identify
current files. Now, while it is relatively easy to create
and maintain such a database (e.g. with a script file and
a chron job), my preference is for something a little
simpler.
The basic problem is that most simple commands (and
graphical file managers) only search inside the current
file folder, so we need to be a little more creative.
Enter the find command. This too, by default,
searches in the current folder, but it is a simple task
to extend the range of the search. In addition, find is
such a powerful command that, once we specify a desired
path, it will do all of the work for us, automatically
scanning the entire directory tree structure below the
specified path.
But, before we continue, let me set the stage on my
particular requirements. The downside to the find command
is that it can be slow, precisely because, by default, it
does search through the entire tree structure. However,
in my case, all of my data files are stored in a single
partition, and the total disk space used in this
partition rarely exceeds 2 GB. In consequence, the number
of files and folders to be scanned is quite manageable.
Combine this with a fast CPU, tons of memory, and a solid
state disk, finding any given file across the entire data
partition is pretty much instantaneous. So, a simple find
command easily suffices for my purposes.
The data partition is mounted as /media/DataDisk in the
root directory, whereas I am normally issuing the find
command from my home folder. Consequently, I use the
command in the form:
find ../../media/DataDisk filename
where the ../ pair changes the folder from
home to root in order to access the data partition and
then search for whatever filename is of
current interest. The filename string can be specific to
a given file, or can include wildcards to broaden the
scope of the search.
Now, this command is still too complex for me to remember
and, since I only need to use it occasionally, I need an
even simpler method. My solution has been to create a
bash script file to ask for the filename string as a user
input and then automatically include this in a search
across my data partition.
The complete script file is as follows:
#! /bin/bash
# Find command used from the home folder in all
sub-folders of DataDisk
# for a case insensitive search of a specific file name
echo 'Enter file name'
read filenam
find ../../media/DataDisk -iname $filenam
echo "Shell command complete"
read
Note that the script requests the search string as the
variable filenam and then includes this
search string in the subsequent find command by calling
up the variable as $filenam. Note also that
the -iname switch has been used in order to make the
search process case insensitive.
The script file is saved as filefind.sh and this file has
its executable bit set so that the script will run in
Terminal. The following screenshot shows the results of
searching for any files with names that include
ticket.
This is just a simple
example of the use of the find command. Additional
criteria can readily be added to make searches quite
specific and/or wide ranging. Furthermore, it is even
possible to combine these with subsequent file actions
such that, for example, files bigger than 250 MB and more
than six months old, can be deleted (http://www.debuntu.org/how-to-find-files-on-your-computer-with-find). As noted earlier, find is a
very powerful command!
Originally published: November, 2012
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