Useful unix scripts:

To copy a file from the current directory to all sub-directories:
find . -type d -exec cp myDriver.java {}/ \;

A bash script for the same:
for d in *; do [[ -d "$d" ]] && cp myDriver.java "$d"; done


Recursively unzip and delete the zip files:
find . -name "*.zip" -exec unzip {} \; -exec /bin/rm {} \;
find . -name "*.gz" -exec gunzip {} \; 

gunzip removes the original gz files. To keep that back write the output to stdout and pipe to a file like this:
gunzip -c hdf-file.gz > hdf-file
or
gzcat hdf-file.txt.gz > hdf-file.txt
If its tarball... use 
gunzip -c hdf-file.tar.gz | tar xvf -


To recursively move pdfs from subfolders to one folder use:
find . -name *.pdf | xargs -I {} mv -iv {} ~/pdf_folder/



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GET FILE COUNT:

file count in current folder and all those in subfolders:
find /folder -type -f | wc -l

file count of only the files in your top folder, but NOT the files in the subfolders of that folder, try this:
ls -l /path/to/folder | grep -v ^d | wc -l


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data extraction:

find . -name "*.gz" -exec gunzip {}  \;
find . -name "*.CP12" | xargs -I {} mv -iv {} .

see file count: 
ls -1R | grep -i .*.CP12 | wc -l


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To enable the system to recognize a custom install app, say /opt/hdf/hdfview create a symbolic link in bin like:
sudo ln -s /opt/hdf/hdfview /usr/local/bin/hdfview

Now hdfview will be available on the command line.


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LINKS:

SED one-liners:
http://sed.sourceforge.net/sed1line.txt

PERL to count freq of words in a file:
http://www.perlmonks.org/?node_id=457784

Advanced BASH scripting docs:
http://www.faqs.org/docs/abs/HTML/index.html

sh scripting:
http://www.ooblick.com/text/sh/


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SCP usage:
scp -P <port> <user>@<server1>:<file with path> <user>@<server2>

List top 5 directories occupying the most space:
du -ah . | sort -n -r | head -n 5