awk/nawk [options] file scan for patterns in a file and process the results
cat [options] file concatenate (list) a file
cd [directory] change directory
chgrp [options] group file change the group of the file
chmod [options] file change file or directory access permissions
chown [options] owner file change the ownership of a file; can only be done
by the superuser
chsh (passwd -e/-s) username login_shell change the user’s login shell
(often only by the superuser)
cmp [options] file1 file2 compare two files and list where differences occur
(text or binary files)
compress [options] file compress file and save it as file.Z
cp [options] file1 file2 copy file1 into file2; file2 shouldn’t already exist. This command creates or overwrites file2.

cut (options) [file(s)] cut specified field(s)/character(s) from lines in
file(s) date [options] report the current date and time
dd [if=infile] [of=outfile] [oper-and=value] copy a file, converting between ASCII and EBCDIC or swapping byte order, as specified

diff [options] file1 file2 compare the two files and display the differences
(text files only)
df [options] [resource] report the summary of disk blocks and inodes free and in use
du [options] [directory or file] report amount of disk space in use
echo [text string] echo the text string to stdout
ed or ex [options] file Unix line editors
emacs [options] file full-screen editor
expr arguments evaluate the arguments. Used to do arithmetic, etc. in the shell.
file [options] file classify the file type
find directory [options] [actions] find files matching a type or pattern
finger [options] user[@hostname] report information about users on local and remote machines
ftp [options] host transfer file(s) using file transfer protocol
grep [options] ‘search string’ argument
egrep [options] ‘search string’ argument
fgrep [options] ‘search string’ argument search the argument (in this case probably a file) for all occurrences of the search string, and list them.

gzip [options] file
gunzip [options] file
zcat [options] file compress or uncompress a file. Compressed files are stored with a .gz ending
head [-number] file display the first 10 (or number of) lines of a file
hostname display or set (super-user only) the name of the current machine
kill [options] [-SIGNAL] [pid#] [%job] send a signal to the process with the
process id number (pid#) or job control number (%n). The default signal is to kill the process.
ln [options] source_file target link the source_file to the target
lpq [options] lpstat [options] show the status of print jobs
lpr [options] file
lp [options] file print to defined printer
lprm [options] cancel [options] remove a print job from the print queue
ls [options] [directory or file] list directory contents or file permissions
mail [options] [user] mailx [options] [user] Mail [options] [user] simple email utility available on Unix systems. Type a period as the first character on a new line to send message out, question mark for help.

man [options] command show the manual (man) page for a command
mkdir [options] directory make a directory
more [options] file
less [options] file
pg [options] file page through a text file
mv [options] file1 file2 move file1 into file2
od [options] file octal dump a binary file, in octal, ASCII, hex, decimal,
or character mode.
passwd [options] set or change your password
paste [options] file paste field(s) onto the lines in file
pr [options] file filter the file and print it on the terminal
ps [options] show status of active processes
pwd print working (current) directory
rcp [options] hostname remotely copy files from this machine to another machine
rlogin [options] hostname login remotely to another machine
rm [options] file remove (delete) a file or directory (-r recursively
deletes the directory and its contents) (-i prompts before removing files)
rmdir [options] directory remove a directory
rsh [options] hostname remote shell to run on another machine script file saves everything that appears on the screen to file until exit is executed

sed [options] file stream editor for editing files from a script or from the
command line
sort [options] file sort the lines of the file according to the options chosen
source file . file read commands from the file and execute them in the
current shell.
source: C shell, .: Bourne shell.
strings [options] file report any sequence of 4 or more printable characters
ending in or . Usually used to search binary files for ASCII
strings.
stty [options] set or display terminal control options
tail [options] file display the last few lines (or parts) of a file
tar key[options] [file(s)] tape archiver–refer to man pages for details on creating, listing, and retrieving from archive files. Tar files can be stored on tape or disk.

tee [options] file copy stdout to one or more files
telnet [host [port]] communicate with another host using telnet protocol
touch [options] [date] file create an empty file, or update the access time
of an existing file
tr [options] string1 string2 translate the characters in string1 from stdin
into those in string2 in stdout
uncompress file.Z uncompress file.Z and save it as a file
uniq [options] file remove repeated lines in a file
uudecode [file] decode a uuencoded file, recreating the original file
uuencode [file] new_name encode binary file to 7-bit ASCII, useful when
sending via email, to be decoded as new_name at destination
vi [options] file visual, full-screen editor
wc [options] [file(s)] display word (or character or line) count for file(s)
whereis [options] command report the binary, source, and man page locations
for the command named
which command reports the path to the command or the shell alias in use
who or w report who is logged in and what processes are running
zcat file.Z concatenate (list) uncompressed file to screen, leaving file compressed on disk