Do Some Basic UNIX

Some basic unix commands

Want more? Try the excellent tutorials at FreeEngineer.org, Mayo, UnixGeeks.org or Idaho state and, of course, the bash manual

Command	Meaning
man function	show the manual page for a function
id	list your personal user id, username, and the groups you belong to.
id username	list username's id, username, and the groups they belong to.
top	shows currently running processes - do not leave this running for more than 30sec (ctrl-c)
ps	show the names of all running processes
mkdir dir_name	create a sub-directory of the current directory
rmdir dir_name	remove a directory. You must remove files in the directory first.
cp source dest	copy a file or directory from source to dest
rm file_name	remove a file (permanent!)
chmod xxx file_name	change the file permissions: Three numbers indicate the permissions for the owner, the group and the world. 1 - execute permission 2 - write permission 4 - read permission You can add these permissions together, for example: 7 - read, write, execute 6 - read and write (not execute) 5 - read and execute (not write) chmod 777 filename Give all users read, write and execute chmod 744 filename owner read, write, execute group members and all others read only chmod 755 filename owner read, write, execute all other read and execute (but not write) chmod 700 filename owner read, write execute others: no access chmod -R will make these changes to all of the files in any sub-directories, as well.
chgrp groupname filename	change the group that has access to the file. For example: chgrp bookheimergroup myWork
ls	list contents of current directory
ls -l	list the contents of the directory (long form, showing sizes)
ls dir_name	list the contents of the named directory
cd dir_name	change to the named directory
pwd	show the name of the current directory
.	the current directory
..	the parent directory of this directory
more file_name	print out the contents of the named (text) file
df	show the free space on the present disk
du	show the disk usage on the system
*	unix wild card - matches all file names (except those beginning with '.') e.g. rm * will remove all files from the current directory! You will absolutely never type 'rm *'. Ever. Always type something like "ls *" first to verify what such a wildcard will match
xemacs file_name textedit file_name nedit file_name vi file_name	These are all text editors that are found commonly on unix systems. Most people seem to prefer xemacs, but each has its adherents.
?	matches any single character