bash Unix Shell

A bash Unix Shell is a Unix Shell managed by GNU.

• Context:
  • It can perform bash Statements.
  • It supports Command History Retrieval. http://en.wikipedia.org/wiki/C_shell#History
  • It supports Unix Process Piping.
  • It can be used to create a bash-based Unix Shell Scripts.
• Example(s)
  • bash v4.
  • bash v3.
  • …
• Counter-Example(s):
  • sh, ksh, tcsh.
  • Powershell.
  • Unix Utility.
• See: Scripting Language, Script Program.

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References

2011

• http://en.wikipedia.org/wiki/Bash_%28Unix_shell%29
  • Bash is a Unix shell written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell (sh). Released in 1989, it has been distributed widely as the shell for ... Bash is a command processor, typically run in a text window, allowing the user to type commands which cause actions. Bash can also read commands from a file, called a script. Like all Unix shells, it supports filename wildcarding, piping, here documents, command substitution, variables and control structures for condition-testing and iteration. The keywords, syntax and other basic features of the language were all copied from sh. Other features, e.g., history, were copied from csh and ksh. Bash is a POSIX shell but with a number of extensions.

    The Bash command syntax is a superset of the Bourne shell command syntax. The vast majority of Bourne shell scripts can be executed by Bash without modification, with the exception of Bourne shell scripts stumbling into fringe syntax behavior interpreted differently in Bash or attempting to run a system command matching a newer Bash builtin, etc. Bash command syntax includes ideas drawn from the Korn shell (ksh) and the C shell (csh) such as command line editing, command history, the directory stack, the $RANDOM and $PPID variables, and POSIX command substitution syntax $(…). When used as an interactive command shell and pressing the tab key, Bash automatically uses command line completion to match partly typed program names, filenames and variable names. The Bash commmand-line completion system is very flexible and customizable, and is often packaged with functions that complete arguments and filenames for specific programs and tasks.

• http://www.gnu.org/software/bash/bash.html
  • Bash is the shell, or command language interpreter, that will appear in the GNU operating system. Bash is a sh-compatible shell that incorporates useful features from the Korn shell (ksh) and C shell (csh). It is intended to conform to the IEEE POSIX P1003.2/ISO 9945.2 Shell and Tools standard. It offers functional improvements over sh for both programming and interactive use. In addition, most sh scripts can be run by Bash without modification.

    The improvements offered by Bash include:

    • Command line editing.
    • Unlimited size command history.
    • Job Control.
    • Shell Functions and Aliases
    • Indexed arrays of unlimited size
    • Integer arithmetic in any base from two to sixty-four

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