ls : list directory contents
man : display the on-line manual pages
pwd : output the current working directory
cd : change directory
less : display file content
cat : concatenate and print files
make : make utility to maintain groups of programs
ps : process status
rm : remove file or directory
cp : copy files
mv : move (rename) a file
mkdir : make directories
chmod : change file modes or access control lists
chown : change file owner and group
grep : file pattern searcher
ssh : secure shell client (remote login program)
kill : terminate a process
exit : exit the shell
head : display first lines of a file
tail : display the last part of a file
wc : word, line, character, and byte count
diff : compare files line by line
echo : display a line of text
history : show and manipulate command history
jobs : print currently running jobs
df : display free disk space
du : display disk usage statistics
tar : manipulate tape!? archives
which : locate a program file in the user's path
date : display or set date and time
