Linux Commands

These commands will work with most (if not all) distributions of Linux as well as most (?) implementations of Unix.

Communication
ftp - File Transfer Protocol.
login - Sign on.
rlogin - Sign on to remote system.
rsh - Run shell or single command on remote system.
talk -Exchange messages interactively with other terminals.
telnet - Connect to another system.
tftp - Trivial file transfer protocol.


Comparisons

cmp - Compare two files, byte by byte.
comm - Compare items in two sorted files.
diff - Compare two files, line by line.
diff3 - Compare three files.

File Management
cat - Concatenate files or display them.
chfn -Change user information for finger, email, etc.
cksum - Compute checksum.
chmod -Change access modes on files.
chsh - Change login shell.
cp - Copy files.
csplit -Break files at specific locations.
dd -Copy files in raw disk form.
file - Determine a file's type.
head - Show the first few lines of a file.
less - Display files by screenful.
ln - Create filename aliases.
ls - List files or directories.
merge - Merge changes from different files.
mkdir -Create a directory.
more - Display files by screenful.
mv - Move or rename files or directories.
newgrp - Change current group.
pwd - Print working directory.
rcp - Copy files to remote system.
rm -Remove files.
rmdir -Remove directories.
split - Split files evenly.
tail - Show the last few lines of a file.
wc - Count lines, words, and characters.


Printing
lpq - Show status of print jobs.
lpr - Send to the printer.
lprm - Remove print job.
lpstat - Get printer status.
pr - Format and paginate for printing.

Programming
ar - Create and update library files.
as - Generate object file.
bison - Generate parsing tables.
cpp - Preprocess C code.
flex - Lexical analyzer.
g++ - GNU C++ compiler.
gcc - GNU C compiler.
ld - Link editor.
m4 - Macro processor.
make - Create programs.
ranlib - Regenerate archive symbol table.
rpcgen - Translate RPC to C code.
yacc - Generate parsing tables.

Program Maintenance
cvs - Manage different versions (revisions) of source files.
etags - Generate symbol list for use with the Emacs editor.
gctags - Generate symbol list for use with the vi editor.
gdb - GNU debugger.
gprof - Display object file's profile data.
imake - Generate makefiles for use with make.
make - Maintain, update, and regenerate related programs and files.
nm - Display object file's symbol table.
patch - Apply patches to source code.
rcs - Manage different versions (revisions) of source files.
size - Print the size of an object file in bytes.
strace - Trace system calls and signals.
strip - Strip symbols from an object file.

Searching
apropos - Search manpages for topic.
egrep - Extended version of grep.
fgrep - Search files for literal words.
find - Search the system for filenames.
grep - Search files for text patterns.
strings - Search binary files for text patterns.
whereis - Find command.

Shell Programming
echo - Repeat command-line arguments on the output.
expr - Perform arithmetic and comparisons.
printf - Format and print command-line arguments.
sleep - Pause during processing.
test - Test a condition.

Storage
bzip2 - Compress files to free up space.
cpio - Create and unpack file archives.
gunzip - Expand compressed (.gz and .Z) files (preferred).
gzip - Compress files to free up space.
shar - Create shell archive.
tar - Copy files to or restore files from an archive medium.
zcat - Display contents of compressed files.

System Status
at - Execute commands later.
atq - Show jobs queued by at.
atrm - Remove job queued by at.
chgrp - Change file group.
chown - Change file owner.
crontab - Automate commands.
date - Display or set date.
df - Show free disk space.
du - Show disk usage.
env - Show environment variables.
finger - Display information about users.
kill - Terminate a running command.
printenv - Show environment variables.
ps - Show processes.
stty - Set or display terminal settings.
who - Show who is logged on.

Text Processing
col - Process control characters.
cut - Select columns for display.
ex - Line editor underlying vi.
expand - Convert tabs to spaces.
fmt - Produce roughly uniform line lengths.
fold - Break lines.
gawk - Process lines or records one by one.
ghostscript - Display PostScript or PDF file.
groff - Format troff input.
ispell - Interactively check spelling.
join - Merge different columns into a database.
paste - Merge columns or switch order.
rev - Print lines in reverse.
sed - Noninteractive text editor.
sort - Sort or merge files.
tac - Print lines in reverse.
tr - Translate (redefine) characters.
uniq - Find repeated or unique lines in a file.
vi - Visual text editor.
xargs - Process many arguments in manageable portions.

Miscellaneous
banner - Make posters from words.
bc - Arbitrary precision calculator.
cal - Display calendar.
clear - Clear the screen.
man - Get information on a command.
nice - Reduce a job's priority.
nohup - Preserve a running job after logging out.
passwd - Set your login password.
script - Produce a transcript of your login session.
su - Become a superuser.
tee - Simultaneously store output in file and send to screen.
which - Print pathname of a command.