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By Graham K. Rogers
Ever since the first Macs appeared, they have been known for the graphical user interface (GUI): icons instead of command line work which before the mid-1980s was the norm. Paradoxically, the arrival of OS X brought with it easy access to the command line should users ever want this, although it is possible to use the computer without ever needing to work at the command line at all.
When users work in UNIX on any operating system (e.g. Linux, Irix) they are insulated from the basics of the operating system itself by a shell. There are several -- some with rather specialised uses. Some users may be familiar with the DOSSHELL file manager that was available with versions of MS DOS.
By default, Terminal in OS X uses Bash: an adaptation of an early shell called Bourne. As an example of the hidden wit that may exist in some computing circles, BASH was so named as it is the Bourne Again Shell. There is a certain wit also to the C Shell.
For most users, there will be no need ever to change the shell, but as users develops skills, they may wish to flex their computer muscles. As there are a number of shells installed with OS X, it is possible out of the box to try them out.
To change to the Bourne shell, the text to enter at the command line is sh, for Shell. Pressing Enter will change the command line and on my computer (with Mountain Lion), this now reads sh-3.2$.
To return to the BASH shell, the text, bash is typed in. When the enter key is the usual computer name and account display is not shown. Instead I see bash-3.2$. This reverts to the normal display when Terminal is restarted.
Other shells that I have found installed on my Mac are:
- C Shell - csh
- Korn Shell ksh
- Z Shell zsh
- TENEX C Shell tcsh
- A windowing shell for Tcl/Tk wish
- Remote Shell rsh
There are a number of other shells available including
- Almquist Shell
- Debian Almquist Shell
- Public domain Korn Shell
- MirBSD Korn Shell
- Perl Shell (psh)
- Scheme Shell (scsh).
- Friendly Interactive Shell (fish) - see below
The above information relates to examining a shell, perhaps before a user decides to use it permanently. If this is wanted, we can use the chpass, chfn or chsh utilities (these are identical) with the -s switch and a space between each part of the command:
chpass -s csh
The user's password will be needed to complete the change and make the new shell the default.
It is also possible to download and install a new shell. One that has found favour with some Mac users is Fish: Friendly interactive shell. The useful online resource, OS X Daily, has an item on how to download and install a development of this: Ridiculous Fish.
There is a fairly informative article on Unix Shells on Wikipedia which also has a number of useful links.
To be continued. . . .
See Also -
New Users and Terminal (1) -- A Quick Look Round
New Users and Terminal (2) -- Basic Navigation
New Users and Terminal (4) -- Lists and Manuals
New Users and Terminal (5) -- Internet Use
New Users and Terminal (6) -- Questions of Identity
New Users and Terminal (7) -- A Little More Discovery
New Users and Terminal (8) -- File Commands and More
New Users and Terminal (9) -- Process Identification and Termination
New Users and Terminal (10) -- Browsing the Web using Unix
New Users and Terminal (11) -- Unix Tricks from OS X Daily
New Users and Terminal (12) -- Installed Text Editors - emacs, nano, pico, vi and vim
New Users and Terminal (13) -- Installing and Using the Utility, WGET
New Users and Terminal (14) -- Passwords, Purging and Closing Notes
New Users and Terminal (15) -- Permissions and chmod
Graham K. Rogers teaches at the Faculty of Engineering, Mahidol University in Thailand. He wrote in the Bangkok Post, Database supplement on IT subjects. For the last seven years of Database he wrote a column on Apple and Macs.
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