Twelve Days of Shell

On the first day of Shell my true love gave to me A list of files in the directory tree …

> ls

On the second day of Shell my true love gave to me Two lines a-laughing …

> cat night-before-christmas.txt | grep "laugh"

On the third day of Shell my true love gave to me Three lines at the beginning …

> head -n 3 night-before-christmas.txt

On the fourth day of Shell my true love gave to me Four lines at the end …

> tail -n 4 night-before-christmas.txt

On just about every Unix and Unix-like operating systems there is a command named ls. ls is short for "list" and can be used to list files in your current working directory. Try sending the command ls in the command box to list all files in the directory.

> cat night-before-christmas.txt | grep -i "^the" 

On the sixth day of Shell my true love gave to me Six lines that are exciting! …

> cat night-before-christmas.txt | grep -i "!" 

On the seventh day of Shell my true love gave to me Seven files that start with “Santa” …

> find Santa* 

On the eighth day of Shell my true love gave to me Eight elves in Santa’s Workhop/ …

> mv Elves/* Workshop

On the ninth day of Shell my true love gave to me Nine names of Santa’s Reindeer …

> find ./ -type f

On the tenth day of Shell my true love gave to me Ten Lords by their names sorted …

> cat lords.txt | sort

On the eleventh day of Shell my true love gave to me Eleven lines with pipers ♫ piping ♫ …

> find -name "piper" -exec grep piping {} \;

On the eighth day of Shell my true love gave to me Eight elves in Santa’s Workhop/ …

> echo "$(<twelve-days-of-shell.txt)"