Useful One liners.

Excellent example of appending the "/home/" in front of all the users name in a file
which has 3222 records.


%s/^/\/home\//g


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 df -hl | awk '{ print $1 "; " "\t" $5}' | sort -n

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AUTOENV=/opt/CA/WorkloadAutomationAE/autouser.PRD/autosys.sh.trs20

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Following command will create 1 GB File system

dd if=/dev/zero of=test.iso2 bs=1024 count=1000000

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Following command will count the file size in GB/MB i.e. in human readable form:

for i in `du -sh * |sort -n |cut -f2`; do du -sh $i; done

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# tar -xvf etc.tar -C test/  ---> Untar the tarball in test directory.

# tar -tvf etc.tar ---> To view the tarball contents without actually extracting.

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Use dd command to create an ISO image

# if=/dev/cdrom of=/datacdimg.iso

thats it!

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# cut -d: '' -f1 passwd ---> Will print first column

# cut -d: -f1,6 passwd ---> will extract user &  home directory.

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awk:bash

awk -F':' '{print $1}' passwd  ---> This will get the first column separated by : ex. passwd file.