sh-2.02$ ls
Unix             as6.soln.txt     notes            temp1
as2.s02.html     assign1.txt      paint.gif        temp2
as3.s02.html     assist.html      schednotes.html  todolist
as4.s02.html     first            script.html      todolist2
as5.s02.html     index.html       second           typescript
as6.s02.html     lab1.html        temp             wordlist
sh-2.02$ file index.html
index.html:	commands text
sh-2.02$ file /usr/bin/zcat
/usr/bin/zcat:	COFF format alpha dynamically linked, demand paged executable or object module stripped - version 3.13-12 
sh-2.02$ cat todolist
Make tacos for dinner
Celebrate national beer day
Pay some of the bills
Take James to karate
Get the car fixed
Find solutions for the Red Black Trees
Grade the 127 assignments
Find a babysitter for Thursday
sh-2.02$ cat todolist2
Make tacos for dinner
Celebrate national beer day
Take a break 
Pay some of the bills
Take James to karate on Sat Morning
Get the car fixed
Find solutions for the Red Black Trees
Find a babysitter for Thursday
sh-2.02$ diff todolist todolist2
2a3
> Take a break 
4c5
< Take James to karate
---
> Take James to karate on Sat Morning
7d7
< Grade the 127 assignments
sh-2.02$ which ls
/usr/bin/ls
sh-2.02$ whereis ls
ls: /sbin/ls /usr/bin/ls /usr/share/man/man1/ls.1.gz
sh-2.02$ apropos sleep
assert_wait_mesg (9r)	- General: Asserts that the current kernel thread is about to block (sleep)
mpsleep (9r)		- General: Blocks the current kernel thread
nanosleep (3)		- Suspend a process from execution for the specified timer interval (P1003.1b)
sleep (1)		- Suspends execution for at least the specified time
sleep (3)		- Suspends execution for an interval of time
sleep (9r)		- General: Puts a calling process to sleep
thread_block (9r)	- General: Blocks (puts to sleep) the current kernel thread
usleep (3)		-  Suspends execution for an interval of time
wakeup (9r)		- General: Wakes up all processes sleeping on a specified address