Unix
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50 free Unix trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Unix began in 1969 as a small side project at Bell Labs and went on to shape almost everything that followed, from the servers behind the web to the phone in your pocket. Its ideas were simple: small tools that each do one job, plain text everywhere, and an easy way of joining programs together. This quiz starts with the basics every beginner meets at the terminal: listing files, moving between directories, reading the documentation and setting permissions. It then works up through the file system, shell scripting and the people and stories behind the system, so the later questions suit readers who already live on the command line. It is written for students learning the command line, developers brushing up before an interview, and anyone curious about where modern computing came from. Every answer comes with a short explanation, so you can play straight through or print the questions for a class.
30 of 50 questions with answers and explanations. Play the quiz
Q 01In which 1990s blockbuster does a child recognise a Unix system and steer a real three-dimensional file browser?
Jurassic Park
Jurassic Park put genuine software on screen: fsn, a 3D file navigator from Silicon Graphics, running on one of the company's own Unix workstations.
Q 02Which software company licensed Unix in the late 1970s and sold its own version under the name Xenix?
Microsoft
Microsoft published Xenix from 1980, years before Windows existed, and by the late 1980s it was probably the most commonly installed Unix of all.
Q 03Which desktop operating system first won official UNIX certification with a release in 2007?
macOS
macOS earned its UNIX 03 registration from The Open Group, the industry consortium that has held the Unix trademark since the 1990s.
Q 04Which free software project, launched by Richard Stallman in 1983, has a recursive name declaring that it is not Unix?
GNU
GNU was designed to work like Unix while containing none of its code, so that anyone could copy, study and change the whole system freely.
Q 05Which Unix-like kernel did a University of Helsinki student release in 1991 after taking a course on Unix?
Linux
Linux was first released on 17 September 1991 by Linus Torvalds, and a modified version of the same kernel now sits inside every Android phone.
Q 06Which programming language did Dennis Ritchie create at Bell Labs, in which the Unix kernel was rewritten in 1973?
C
C grew out of an earlier Bell Labs language called B, and rewriting Unix in it made the system far easier to move to new kinds of computer.
Q 07Bell Labs, where Unix was written in 1969, was the research arm of which American telephone giant?
AT&T
AT&T was barred by a 1956 antitrust settlement from any business but communications, so Unix could not be sold and went out for the cost of media and shipping.
Q 08Which username conventionally belongs to the Unix superuser, the all-powerful account whose user ID number is zero?
root
root may read, change or delete anything on the system, and BSD systems often add a backup account called toor, the same name spelled backwards.
Q 09Which text encoding was first sketched on a placemat in a New Jersey diner in 1992 by two Unix veterans?
UTF-8
UTF-8 was up and running within days of that sketch, and since 2008 it has been the most common text encoding on the World Wide Web.
Q 10Which nickname describes a Unix process that has finished running but still holds an entry in the process table?
Zombie
Zombie processes linger only until the parent program reads their exit status, at which point the dead entry is said to be reaped.
Q 11Which Unix command prints the names of the files in a directory, and adds sizes, owners and dates when given -l?
ls
ls is short for list, and a command of that name has been part of Unix since the very first version of the system.
Q 12Which Unix command changes the working directory, and returns to the user's home directory when typed with no arguments?
cd
cd is usually built into the shell itself, because a separate program could change only its own directory and never the shell's.
Q 13Which three-letter Unix command, built into many shells, reports the directory in which a user is working?
pwd
pwd is short for print working directory, and it has been part of Unix since the fifth version of the system.
Q 21Which Unix command sends a signal to a running process, by default the termination request known as SIGTERM?
kill
kill is something of a misnomer, because it can deliver any signal at all, and a program may catch the default one and tidy up before exiting.
Q 22Which Unix command shows the closing lines of a file, and with the option -f keeps watching a growing log?
tail
tail prints the final ten lines unless told otherwise, and its follow option then adds each new line as another program writes it.
Q 23Which two-letter Unix command reports how many lines, words and bytes a file contains?
wc
wc stands for word count, and given the option -l it prints only the number of lines, a favourite way to count the results of another command.
Q 14Which Unix command, named after a word meaning to chain together, writes one or more files to standard output?
cat
cat is short for catenate, a variant of concatenate, and given several file names it writes them out end to end as a single stream.
Q 15Which Unix command displays the reference page for another command, taken from eight numbered sections?
man
man is short for manual, and its pages still follow a format set out in 1971 for the first Unix Programmer's Manual.
Q 16Which Unix command, run with the options -r and -f, nearly erased Pixar's Toy Story 2 during production in 1998?
rm
rm destroyed about 90 per cent of two years' work, and the film survived only because a technical director kept a backup on her home computer.
Q 17Which Unix search command, by one account, was written to help analyse who wrote the Federalist Papers?
grep
grep is named after g/re/p, the ed editor instruction that searches globally for a regular expression and prints every matching line.
Q 18Which Unix command sets who may read, write or run a file, accepting octal modes such as 755?
chmod
chmod is short for change mode, and each octal digit is a sum in which read counts 4, write counts 2 and execute counts 1.
Q 19Which Unix command sends its arguments back to the terminal, the usual way a shell script shows a message?
echo
echo joined Unix in its second version, after Doug McIlroy programmed it as what he called a finger exercise and it proved useful.
Q 20Which two-letter Unix command both renames a file and carries it to a different directory?
mv
mv merely relabels a file when both names sit on the same file system, so even an enormous file moves without its data being touched.
Q 24Which Unix filter collapses adjacent identical lines into one, so its input is usually run through sort first?
uniq
uniq compares only neighbouring lines, and its counting option prefixes each surviving line with the number of times it occurred.
Q 25Which Unix command, first developed for writing to magnetic tape drives, bundles many files into one archive file?
tar
tar is short for tape archive, and the single bundled files it produces are popularly known as tarballs.
Q 26Which Unix pager, written by Mark Nudelman in the 1980s, was named as a joke on the older pager called more?
less
less added the one thing its predecessor lacked, scrolling backwards through a file, and it opens huge files at once because it never reads the whole file first.
Q 27Which Unix command prints September 1752 with eleven days missing, as Britain left the Julian system?
cal
cal follows British history, so its page for September 1752 jumps straight from the 2nd to the 14th.
Q 28Which screen editor did Bill Joy write in the 1970s, a program every certified UNIX system must still include?
vi
vi takes its name from the visual mode of an older line editor called ex, and the two have always been one and the same program.
Q 29Which Unix text tool, developed at Bell Labs by Lee McMahon, is best known for its s command that substitutes text?
sed
sed is short for stream editor, and it began as a wish for a substitution tool to sit beside Unix's pattern-searching command.
Q 30Which Unix scheduler, named after the Greek word for time, runs commands at moments set out in five fields?
cron
cron takes its orders from tables called crontabs, in which a row of five asterisks means run the job every single minute.