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Operating System Tools
Notes SKsh is an AmigaOS version, that provides various Amiga-specific features like ARexx
interoperability.
Another commercial ksh reimplementation is MKS Inc.’s MKS Korn shell. It was included with
Microsoft’s Services for Unix (SFU) up to version 2.0. As per David Korn, the MKS Korn shell was
not completely compatible with his own Korn shell implementation in 1998.
When the SFU Version 3.0 was introduced, Microsoft has substituted the MKS Korn shell
with a new and fully POSIX compliant Korn shell as part of the new native Interix subsystem
technology. It is supported on Windows NT 4.0 SP6a+, Windows 2000, Windows XP Professional
and Windows Server 2003. It is also available in the Subsystem for UNIX-based Applications
(SUA) of Windows Vista Enterprise and Ultimate Editions and Windows Server 2008.
7.2.4 TCSH
TCSH is considered as an improved version of the Berkeley UNIX C shell. However, it is a
completely compatible version of C shell. It is a command language interpreter usable both as an
interactive login shell and a shell script command processor. It includes a command-line editor,
programmable word completion, spelling correction, a history mechanism and job control.
We can call TCSH a programming language with conditional statements. In tcsh, the ‘t’ occurs
from the T in TENEX. TENEX is an operating system which encouraged Ken Greer, the author
of tcsh, with its command-completion feature. Ken Greer worked on tcsh in the late 1970s at
Carnegie Mellon University. Paul Placeway from The Ohio State University continued work on
it in the 1980s, and since then it has been maintained by numerous people. Wilfredo Sanchez, the
former lead engineer of Mac OS X, worked on tcsh in the early 1990s at MIT. Early editions of
Mac OS X shipped with tcsh as the default shell, however the default for new accounts is bash
as of 10.3.
!
Caution Iowa State’s implementation of MIT’s Project Athena (Project Vincent) by default
uses tcsh as the default shell, even though users can change this.
TCSH is considered as the default shell of FreeBSD and its descendants such as PC-BSD,
DragonFly BSD, and DesktopBSD.
Task Make distinction between ksh and tcsh shell.
Self Assessment
Fill in the blanks:
6. ............................................ is the default shell on most systems built on top of the Linux
kernel as well as on Mac OS X.
7. The ............................................ is a Unix shell developed by Bill Joy for the BSD Unix system.
8. The ............................................ shell is backwards-compatible with the Bourne shell and
includes many features of the C shell as well.
9. ............................................ is a command language interpreter usable both as an interactive
login shell and a shell script command processor.
10. ............................................ provides access to the Tk widget toolkit.
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