SIMPLE UNIX COMMANDS

 

Here is a short introduction to unix commands.

 

To obtain more information on a command type man command name.

Man stands for manual and gives you the pages of a manual on the command.

 

To begin with a set of commands to look at files and to find information on them.

 

To list the contents of a file... more filename

To list the end of a file... tail filename

To list the entire contents of a file at once... cat filename

To list the files in the current directory... ls or ls | more

To list the files including invisible ones... ls -a or ls -a | more

To list the files and their characteristics... ls -al or ls -al | more

 

To copy a file... cp file1 file2

To move a file (i.e. rename it)... mv filename newfilename

To delete a file... rm filename

 

In unix the disk space assigned to a user can be divided up into directories.  These directories are like folders in windows and thus are useful for placing together a set of files that are related to each other.

 

To make a directory... mkdir directoryname

To change directory... cd directoryname

To find one's current directory name... pwd

To copy a file to a directory… cp file directoryname/file

To move a file to a directory… mv file directoryname/file

 

Here are a few commands that may be of use.

 

To search a file for a given string of characters... grep 'string' filename

To list the processes running on the machine... ps -ef | more

To list your processes running on the machine... ps -ef | grep yourusername

 

To stop something you do not want anymore,

you will have to get the process number by ps -ef... kill -9 processnumber

 

 

Vi editor

 

To alter the information in a file (or to create a file with new data in it) you will use the vi editor.  This is not the most sophisticated of editors, but it occurs on most unix systems.

 

One key thing to remember about vi is that it has two modes of operation.  The input mode allows you to enter new information into the file. To turn this mode off, press the esc key.   The other mode allows you to move around the file and alter the data or information that is already there.

 

To create a file or alter an existing file type vi filename and then press return. Once in vi use the following commands.

 

To insert text in the middle of a line, move the cursor to where you want to insert then press i and type your text in. Press the esc key to turn off insert mode.

 

To insert a new line between two lines press o with the cursor on the line above. The esc key turns off the insert mode.

 

To move the cursor use the h j k l keys. h moves left, j down, k up and l right.

 

To delete some text put the cursor on the character to be deleted and press x.

 

To delete a line, move to the line you want to delete and press d twice (i.e.dd)

 

If you make a mistake (not in input) try typing u (for undo), it does not always work,

but it is worth a try.

 

To leave the editor pess the shift key and hold it down then type ZZ.

 

To abort out of the editor type :q!

 

To go to the top of a file type 1G (note it is captital G)

 

To go to the bottom of a file type G (note it is capital G)

 

To go to a specific line number type :linenumber then press return.

 

To find a text string /string then press return.

 

To set line numbers :set line number then press return

 

To replace one string by another between linex and liney :linex,lineys/string1/string2/cg then press return

 

 

 

XTERMINALS

 

to get an xterm... xterm &

 

 

 

 

FILE TRANSFER

 

To transfer files to another machine (you will need the machine name or the machine number)... sftp machine name/number

 

Then login to the remote machine at the prompt. To get a file type get file name then press return or to put a file type put filename (followed by return). mput and mget can be used to transfer more than one file with a single command. You can use the cd command to change directories on the remote machine.

 

 

REMOTE LOGIN TO ANOTHER MACHINE

 

To access another machine you can

 

ssh -l username machine name/number then press return.

You should then get a prompt for your password.

 

ALIAS

 

If you do not like the command as it is given you in unix then use the alias command to change it to what you do like. For example you may use an abreviation of a command rather than the full command name. Thus grep could be made to gr by alias gr 'grep'.

 

 

FOR MORE INFORMATION

 

A possible source for more information on unix is

B.W.Kerighan and R.Pike The Unix Programming Enviroment.