cut

purpose: remove sections from lines within files

example file, message.txt:

TheNewThinkTank has recently reached 1,030 contributions in the last year! Wow!

example, print the first character of a file:
cut -b 1 message.txt

-b: select by byte
-c: select by character
-d: select by delimiter
-f: select by field

example, print the first character of a file:
cut -b 7,8,9,10,11 message.txt
better, if the characters are sequential:
cut -b 7-11 message.txt

more consistently (to avoid if a character takes more than 1 byte),
cut -c 7-11 message.txt

example: choose multiple character intervals:
cut -b 7-11,56,57-61 message.txt

example, split a file by field:
by default, tab \t is the delimeter.
change the delimeter to space instead:
cut -d " " -f 1,2 message.txt

example: extract usernames
cat /etc/passwd

cut -d ":" -f 1 /etc/passwd

cut is best used on files with multiple rows and fields