Exercise: Find commands you have never used
You are given four jobs and no command names. Find each command with a keyword search, check it, and run it on workstation. Then dig into a package's own documentation.
Find commands you have never used
- Turn a description of a job into a keyword search.
- Narrow a search that finds too much.
- Find documentation that is not a manual page.
How long has workstation been running?
Search the manual for a phrase that describes the job, then run the command you find.
[student@workstation ~]$ man -k "how long"
uptime (1) - Tell how long the system has been running.
[student@workstation ~]$ uptime
10:10:58 up 43 min, 0 users, load average: 0.00, 0.03, 0.00Chapter 8 explains the load average numbers.
Show this month's calendar
[student@workstation ~]$ man -k calendar
cal (1) - display a calendar
[student@workstation ~]$ cal 10 2026
October 2026
Su Mo Tu We Th Fr Sa
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31man cal shows that it also accepts a month and a year.
How much memory is free?
A search for memory alone finds dozens of programmer pages. Narrow it: use a more specific phrase, or limit it to section 1.
[student@workstation ~]$ man -k memory | head -5
aligned_alloc (3) - allocate aligned memory
alloca (3) - allocate memory that is automatically freed
calloc (3) - allocate and free dynamic memory
cfree (3) - free allocated memory
chmem (8) - configure memory
[student@workstation ~]$ man -k "free and used memory"
free (1) - Display amount of free and used memory in the system
[student@workstation ~]$ free -h
total used free shared buff/cache available
Mem: 1.9Gi 376Mi 1.4Gi 23Mi 320Mi 1.5Gi
Swap: 0B 0B 0Bman -k -s 1 memory would also have cut the list down, to commands only. -h gives readable sizes here too, as it did for ls.
Which echo runs?
echo exists both as a shell built-in and as a program. type -a lists every match, in the order the shell tries them.
[student@workstation ~]$ type -a echo
echo is a shell builtin
echo is /usr/bin/echoThe built-in wins, so help echo describes the echo you actually use, while man echo describes /usr/bin/echo. They behave almost identically.
Read a package's own documentation
chrony keeps workstation's clock right. Look at what its package installed under /usr/share/doc, and read the start of its README.
[student@workstation ~]$ ls /usr/share/doc/chrony
FAQ NEWS README
[student@workstation ~]$ head -n 8 /usr/share/doc/chrony/README
This is the README for chrony.
What is chrony?
===============
chrony is a versatile implementation of the Network Time Protocol (NTP).
It can synchronise the system clock with NTP servers, reference clocks
(e.g. GPS receiver), and manual input using wristwatch and keyboard.The FAQ answers common configuration questions that the manual pages don't. Chapter 11 configures chrony.