Qshell is an optional
command-line interpreter
A command-line interface (CLI) is a means of interacting with software via commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternativ ...
(
shell
Shell may refer to:
Architecture and design
* Shell (structure), a thin structure
** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses
Science Biology
* Seashell, a hard outer layer of a marine ani ...
) for the
IBM i operating system. Qshell is based on
POSIX
The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with comm ...
and
X/Open X/Open group (also known as the Open Group for Unix Systems and incorporated in 1987 as X/Open Company, Ltd.) was a consortium founded by several European UNIX systems manufacturers in 1984 to identify and promote open standards in the field of info ...
standards. It is a
Bourne-like shell that also includes features of
KornShell
KornShell (ksh) is a Unix shell which was developed by David Korn (computer scientist), David Korn at Bell Labs in the early 1980s and announced at USENIX Annual Technical Conference, USENIX on July 14, 1983. The initial development was base ...
.
The utilities (or
commands) are external programs that provide additional functions. The development team of Qshell had to deal with platform-specific issues such as translating between
ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...
and
EBCDIC
Extended Binary Coded Decimal Interchange Code (EBCDIC; ) is an eight- bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems. It descended from the code used with punched cards and the corresponding si ...
. The shell supports
interactive mode as well as
batch processing
Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...
and can run
shell script
A shell script is a computer program designed to be run by a Unix shell, a command-line interpreter. The various dialects of shell scripts are considered to be command languages. Typical operations performed by shell scripts include file manipu ...
s from
Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...
operating systems with few or no modifications.
Commands
The following is a list of
commands that are supported by the Qshell
command-line interpreter
A command-line interface (CLI) is a means of interacting with software via commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternativ ...
on IBM i 7.4.
Differences from other Unix shells
Qshell does not support the
redirection operator or provide a
command history
Command history is a feature in many operating system shells, computer algebra programs, and other software that allows the user to recall, edit and rerun previous commands.
Command line history was added to Unix in Bill Joy's C shell of 1978; ...
. It also has no
job control support as IBM i operating system does not have the concept of a
foreground or
background process
A background process is a computer process that runs ''behind the scenes'' (i.e., in the background) and without user intervention. Typical tasks for these processes include logging, system monitoring, scheduling, and user notification.
On a Wind ...
group. The POSIX standard
and
built-in commands are therefore not available as well.
Compared to PASE for i
According to IBM, QSHELL is a “
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
-like” interface built over
IBM i
IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS in 2 ...
. The commands issued by the user point to programs in a “Qshell” library. It began as a port from the
ash shell, which was a
Bourne-like shell created by
Berkeley Software Design
Berkeley Software Design, Inc. (BSDI or, later, BSDi), was a software company founded in 1991 by members of the Computer Systems Research Group (CSRG), known for developing and selling BSD/OS (originally known as BSD/386), a commercial and part ...
.
See also
*
Control Language
The Control Language (CL) is a scripting language originally created by IBM for the System/38 Control Program Facility and later used in OS/400 (now known as IBM i). It bears a resemblance to the IBM Job Control Language and consists of a set ...
*
Comparison of command shells
This article catalogs comparable aspects of notable operating system shell (computing), shells.
General characteristics
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...
References
Further reading
*
*
External links
*
Exploring iSeries QSHELL
{{Unix shells
Command shells
Interpreters (computing)
IBM operating systems