Invitation to learn: Console tips for Linux beginners
By Sven Appel Oct 22, 2006, 10:40 GMT
Hamburg - For many computer users, it sounds like a nightmare - being forced to enter cryptic commands into the computer using the keyboard. Yet, it need not be such a horror show. While operating systems like Windows XP and Mac OS and many Linux versions allow the user to control the computer completely using the mouse, it can be helpful to enter commands in text form sometimes. Linux offers a powerful tool for this, known as the console or shell.
A command consists of a series of letters or symbols capped off by the return key. The command is then evaluated by a command interpreter, known as the shell. There are various shells.
'But beginners don't need to pull their hair out using them,' says Elisabeth Staegemann, a Linux instructor at the Adult Education Centre in Hamburg. Most Linux versions are set to work with a shell called bash. On the graphic interface, the shell or console is usually symbolized by a small monitor. It can be called up with a mouse click.
Users learning to use the shell for the first time should be sure that they are logged in as a normal user, says Martin Lasarsch from Suse Linux in Dusseldorf, which is probably the most popular Linux distribution in Germany. That way it's hard to do anything catastrophic. If new software is to be installed or a new user created, then it's always possible to enter the command 'su' to log in as an administrator, which is known in Linux as 'root.'
The mouse is generally a problem-free way of configuring and administering Linux systems. A good example of this 'Yast,' a program to make it easier for users of Suse Linux to set up their computers, peripheral devices, and internet connection. 'Roughly 90 per cent of the users work without console,' Lasarsch estimates. 'Yet if problems arise, then the console can be very helpful.'
If, for example, the graphic user interface refuses to start because the graphics card is making trouble, then the computer can always be controlled using the console, says Elisabeth Staegemann. The shell also offers more information about software and hardware, says Carsten Raddatz from newthinking communications, a collective group of Berlin companies that work with free software.
The console is also helpful for automating a specific set of instructions: using a 'cron' command, the computer can be set to complete tasks at specific times.
'I've set up my computer at home to retrieve an update every morning,' is one example of automation cited by Lasarsch. It's also possible to use the console to enter a command whereby the computer checks the email inbox hourly for new mail.
'Many things are simpler and easier to do using the shell,' says IT systems administrator Carsten Raddatz. By default, searching for a file with the Konqueror file explorer included in the graphic interface first opens the personal directory of the logged-in user.
'You must then click your way through until you find the desired file. Yet with the console you can do it with one single command.' The same is true if a CD is to be burned or songs are to be converted into MP3 files.
Commands entered using the console can also be modified using options. That allows them to be more effectively customised to the user's needs. The Grep command, for example, serves as a kind of full-text search, for the graphic user interface as well. In the shell, however, it's possible to set options to refine the search to the point where it can even search for highly specific things like anagrams, words that read the same forwards and backwards.
One of the most important commands is the pipe command: this redirects the results of a previously executed command to another program. This is helpful for reading the contents of a file and at the same time making that text available to an email program in the event that the contents should be forwarded to a friend.
'That saves the time needed to copy the text,' Roddatz says.
'You don't have to learn the commands by heart to work with the shell,' says Staegemann. It's more important that users understand the system as a whole. And working with the console is a big help in doing so, since it makes the many interconnections evident. 'The console is an invitation to learn,' says Raddatz.© 2006 dpa - Deutsche Presse-Agentur