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Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell.〔 〕〔 〕 Released in 1989,〔 〕 it has been distributed widely as the shell for the GNU operating system and as a default shell on Linux and . It has been ported to Microsoft Windows and distributed with Cygwin and MinGW, to DOS by the DJGPP project, to Novell NetWare and to Android via various terminal emulation applications. In the late 1990s, Bash was a minor player among multiple commonly used shells; at present Bash has overwhelming favor. Bash is a command processor that typically runs in a text window, where the user types commands that cause actions. Bash can also read commands from a file, called a script. Like all Unix shells, it supports filename globbing (wildcard matching), 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 name itself is an acronym, a pun, and a description. As an acronym, it stands for ''Bourne-again shell'', referring to its objective as a free replacement for the Bourne shell.〔(C Programming ) by Al Stevens, Dr. Dobb's Journal, July 1, 2001〕 As a pun, it expressed that objective in a phrase that sounds similar to ''born again'', a term for spiritual rebirth.〔 〕〔 〕 The name is also descriptive of what it did, ''bashing together'' the features of sh, csh, and ksh.〔 〕 A security hole in Bash dating from version 1.03 (August 1989), dubbed Shellshock, was discovered in early September 2014. == History == Brian Fox began coding Bash on January 10, 1988〔 〕 after Richard Stallman became dissatisfied with the lack of progress being made by a prior developer.〔 Stallman and the Free Software Foundation (FSF) considered a free shell that could run existing shell scripts so strategic to a completely free system built from BSD and GNU code that this was one of the few projects they funded themselves, with Fox undertaking the work as an employee of FSF.〔〔 〕 Fox released Bash as a beta, version .99, on June 8, 1989〔 and remained the primary maintainer until sometime between mid-1992〔 〕 and mid-1994, when he was laid off from FSF〔 〕 and his responsibility was transitioned to another early contributor, Chet Ramey.〔 〕〔 〕〔 〕 In September 2014, Stéphane Chazelas, a Unix/Linux, network and telecom specialist working in the UK,〔https://www.linkedin.com/pub/st%C3%A9phane-chazelas/7/2a2/834〕 discovered a security bug in the program. The bug, first disclosed on September 24, was named Shellshock and assigned the numbers (CVE-2014-6271 ), CVE-2014-6277〔https://cve.mitre.org/cgi-bin/cvename.cgi?name=2014-6277〕 and (CVE-2014-7169 ). The bug was regarded as severe, since CGI scripts using Bash could be vulnerable, enabling arbitrary code execution. The bug is related to how Bash passes function definitions to subshells through environment variables. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bash (Unix shell)」の詳細全文を読む スポンサード リンク
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