Developer(s) | IBM |
---|---|
Operating system | IBM i |
Platform | IBM Power Systems |
Standard(s) | POSIX, X/Open |
Available in | English |
Type | Command shell |
Website | Qshell |
Qshell is an optional command-line interpreter (shell) for the IBM i operating system. Qshell is based on POSIX and X/Open standards. It is a Bourne-like shell that also includes features of KornShell. [1] 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 and EBCDIC. The shell supports interactive mode as well as batch processing and can run shell scripts from Unix-like operating systems with few or no modifications. [1]
The following is a list of commands that are supported by the Qshell command-line interpreter on IBM i 7.4. [2]
Qshell does not support the <>
redirection operator or provide a command history. It also has no job control support as IBM i operating system does not have the concept of a foreground or background process group. The POSIX standard fg
and bg
built-in commands are therefore not available as well. [3]
According to IBM, QSHELL is a “Unix-like” interface built over IBM i. 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. [1]
Bash, short for Bourne-Again SHell, is a shell program and command language supported by the Free Software Foundation and first developed for the GNU Project by Brian Fox. Designed as a 100% free software alternative for the Bourne shell, it was initially released in 1989. Its moniker is a play on words, referencing both its predecessor, the Bourne shell, and the concept of rebirth.
KornShell (ksh
) is a Unix shell which was developed by David Korn at Bell Labs in the early 1980s and announced at USENIX on July 14, 1983. The initial development was based on Bourne shell source code. Other early contributors were Bell Labs developers Mike Veach and Pat Sullivan, who wrote the Emacs and vi-style line editing modes' code, respectively. KornShell is backward-compatible with the Bourne shell and includes many features of the C shell, inspired by the requests of Bell Labs users.
The Portable Operating System Interface 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 command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers.
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 manipulation, program execution, and printing text. A script which sets up the environment, runs the program, and does any necessary cleanup or logging, is called a wrapper.
A Unix shell is a command-line interpreter or shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts.
uniq
is a utility command on Unix, Plan 9, Inferno, and Unix-like operating systems which, when fed a text file or standard input, outputs the text with adjacent identical lines collapsed to one, unique line of text.
The Bourne shell (sh
) is a shell command-line interpreter for computer operating systems.
tr is a command in Unix, Plan 9, Inferno, and Unix-like operating systems. It is an abbreviation of translate or transliterate, indicating its operation of replacing or removing specific characters in its input data set.
In most Unix and Unix-like operating systems, the ps
program displays the currently-running processes. The related Unix utility top
provides a real-time view of the running processes.
In computing, kill
is a command that is used in several popular operating systems to send signals to running processes.
In computing, cmp
is a command-line utility on Unix and Unix-like operating systems that compares two files of any type and writes the results to the standard output. By default, cmp
is silent if the files are the same; if they differ, the byte and line number at which the first difference occurred is reported. The command is also available in the OS-9 shell.
mv
is a Unix command that moves one or more files or directories from one place to another. If both filenames are on the same filesystem, this results in a simple file rename; otherwise the file content is copied to the new location and the old file is removed. Using mv
requires the user to have write permission for the directories the file will move between. This is because mv
changes the content of both directories involved in the move. When using the mv
command on files located on the same filesystem, the file's timestamp is not updated.
In computing, tee
is a command in command-line interpreters (shells) using standard streams which reads standard input and writes it to both standard output and one or more files, effectively duplicating its input. It is primarily used in conjunction with pipes and filters. The command is named after the T-splitter used in plumbing.
test is a command-line utility found in Unix, Plan 9, and Unix-like operating systems that evaluates conditional expressions. test was turned into a shell builtin command in 1981 with UNIX System III and at the same time made available under the alternate name [.
In computing, sleep is a command in Unix, Unix-like and other operating systems that suspends program execution for a specified time.
expr is a command line utility on Unix and Unix-like operating systems which evaluates an expression and outputs the corresponding value. It first appeared in Unix v7. The command is available for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities. The expr command has also been ported to the IBM i operating system.
In computing, a shebang is the character sequence #!, consisting of the characters number sign and exclamation mark, at the beginning of a script. It is also called sharp-exclamation, sha-bang, hashbang, pound-bang, or hash-pling.
od
is a command on various operating systems for displaying ("dumping") data in various human-readable output formats. The name is an acronym for "octal dump" since it defaults to printing in the octal data format.
getopts
is a built-in Unix shell command for parsing command-line arguments. It is designed to process command line arguments that follow the POSIX Utility Syntax Guidelines, based on the C interface of getopt.