linux bash what does it mean

linux bash is a command processor that usually runs in a text window and can execute commands entered directly by the user; Bash can also read commands from files, such files are called scripts; and other Unix Like the shell, it supports file name substitution, pipes, here documents, command substitution, variables, and more.

#The operating environment of this article: linux5.9.8 system, Dell G3 computer.

What does linux bash mean?

Bash, a type of Unix shell, was written by Brian Fox in 1987 for the GNU project. The first official version was released in 1989. It was originally planned to be used on the GNU operating system, but it can run on most Unix-like operating systems, including Linux and Mac OS X v10.4, which use it as the default shell.

Bash is a later-compatible and open-source version of the Bourne shell. Its name comes from a pun on the Bourne shell (sh) (Bourne again / born again): Bourne-Again SHell.

Bash is a command processor that usually runs in a text window and can execute commands entered directly by the user. Bash can also read commands from files, called scripts. Like other Unix shells, it supports file name substitution (wildcard matching), pipes, here documents, command substitution, variables, and structural control statements for conditional judgment and loop traversal. All basic features including keywords and syntax are borrowed from sh. Other features, such as historical commands, are borrowed from csh and ksh. In general, although Bash is a shell that meets the POSIX specification, it has many extensions.

A security vulnerability called Shellshock was discovered in early September 2014 and quickly led to a series of attacks on the Internet. This vulnerability dates back to version 1.03, released in 1989.

The command syntax of bash is a superset of the Bourne shell command syntax.

Most of the large number of Bourne shell scripts can be executed in bash without modification. Only those scripts that reference Bourne special variables or use Bourne's built-in commands need to be modified. Many of bash's command syntax comes from Korn shell (ksh) and C shell (csh), such as command line editing, command history, directory stack, $RANDOM and $PPID variables, and POSIX command substitution syntax: $(...). As an interactive shell, pressing the TAB key can automatically complete the partially entered program name, file name, variable name, etc.

Bash's function declarations are incompatible with Bourne/Korn/POSIX scripts when using the 'function' keyword (the Korn shell has the same problem). However, Bash also accepts Bourne/Korn/POSIX function declaration syntax. Because of many differences, Bash scripts rarely run in the Bourne or Korn interpreters unless the script is written with compatibility in mind. However, as Linux becomes more popular, this approach is becoming less and less common. However, in POSIX mode, Bash is more POSIX compliant.

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