Useful_linux_commands

Get the md5sum for files in a directory
----------------------------------------
$ ls | xargs md5sum

If the file name contains white space, set the delimiter to new line (default delimiter is white space)
$ ls | xargs -d'\n' md5sum

Estimate the directories / files size 
$ ls | xargs du -sh 

Get the result sorted
$ ls | xargs du -s | sort -n

Square root of 2 in 100 decimal 
$ echo 'scale=100; sqrt(2)' | bc

extract file.tar.gz or file.tgz
$ tar -xvzf file.tar.gz

create file.tar.gz or file.tgz
$ tar -cvzf filename.tar.gz file(s)

extract file.tar.bz2 or file.tbz2
$ tar -xvjf file.tar.bz2

create file.tar.bz2 or file.tbz2
$ tar -cvjf filename.tar.bz2 file(s)

x --> extract
c --> create
v --> verbose
z --> deal with gun zipped files
j --> deal with bzipped files
f --> read from a file

exclude files when do a grep 
$ grep -r --exclude="*.log" PATTERN *

delete everything inside a quote in VIM
>>> di"

unzip multiple zip files
$ ls | xargs -n1 unzip

Create random text file (human readable) [10M]
base64 /dev/urandom | head -c 10485760 > file.txt


view jars content
jar tvf jarName.jar | less

acquire a heap dump
jmap -dump:format=b,file=heapdump.hprof <pid>

convert images to pdf
convert-im6 img1.jpg img2.jpg img3.jpg document.pdf