hostname : computer's network name
pwd : print working directory
mkdir : make directory
cd : change directory
cd .. : return to previous directory
ls : list directory
rmdir : remove directory
rm -rf : remove non-empty directory
touch : create new file
rm : remove file
python -m SimpleHTTPServer : create localhost
tab : auto completion
ctrl + i : search previous commands
ctrl + l : clear window
| (pipe) : running multiple commands
cat : print out content of file
head : print out first 10 lines
head -n number : print out a certian number of lines
head > : send output to a new file
head >> : append output to file
tail : print out last 10 lines
tail -n number :
grep "searchterm"
-i : case insensitive
-w : exact word
-r : recurring
" * " (Asterisk) : within every file
-A number : print out line with match and 4 lines after
-B number : print out line with match and 4 lines before
-C number : print out line with match and 4 lines before and 4 lines after
-l : print out filenames that match search
-n: show line numbers along matching lines