Here’s a fun survey question: name as many two-character Unix commands as you can and say what they do.
Let’s be precise about what we mean by a “command”:
- Shell aliases like
la
are not commands. - Shell built-in commands count as commands; over time the shell incorporated directly things that were previously separate executables in Unix.
- Commands not available in a wide variety of Unix distributions by default don’t count. In other words, if you have to install some optional package to get the command then it isn’t a “Unix” command.
- Optional: Only allow commands included in a “classic” Unix from Bell Labs.
Ready? Let’s go.
Command | Description |
---|---|
ar |
Archive librarian |
as |
Assembler |
at |
Execute commands at a later time |
bc |
Arbitrary precision calculator |
bg |
Run suspended command in the background |
cc |
C compiler |
cd |
Change directory |
cp |
Copy files |
dc |
Desk calculator |
dd |
Convert and copy files |
df |
Disk free space |
du |
Disk usage |
ed |
Line-oriented editor |
ex |
Extended line-oriented editor |
fg |
Resume suspended command in the foreground |
ln |
Make soft links |
lp |
Print files |
ls |
List files |
m4 |
Macro processor |
mt |
Magnetic tape control |
mv |
Move files |
nl |
Number lines |
nm |
Dump symbol table information |
od |
Octal dump |
pr |
Prepare files for printing |
ps |
Process status |
rm |
Remove files |
sh |
Shell |
su |
Super user |
tr |
Translate characters |
ul |
Underlining |
vi |
Visual editor |
wc |
Word count |
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