1 shell
shell: Command interpreter, which executes the corresponding command according to the input command.
1.1 The shell family
Check which shells are available on the current system:
cat /etc/shells
View the shell currently in use by the system
echo $SHELL
common shell
/bin/sh (replaced by /bin/bash)
/bin/bash (the default Linux shell)
/bin/ksh (Kornshell developed by AT&T Bell lab., compatible with bash)
/bin/tcsh (integrated C Shell, provides more functions)
/bin/csh (has been replaced by /bin/tcsh)
/bin/zsh (a more powerful shell based on ksh)
2.2 bash
bash is a Unix shell written for the GNU Project. Its name is a series of acronyms: Bourne-Again
SHell — a pun on the Bourne shell (sh) (Bourne again / born again)
bash is the default shell on many Linux platforms, and in fact, many traditional UNIX Shells used, such as
tcsh, csh, ash, bsh, ksh, etc., are roughly the same as Shell Scripts. After you learn one kind of Shell,
other Shells will quickly get started. Usually can be
used .
bash is the default shell on most Linux systems and Mac OS X v10.4, it can run on most Unix-style
operating systems, and has even been ported to Cygwin on Microsoft Windows to implement the
POSIX virtual interface for windows . Additionally, it was ported to MS-DOS by the DJGPP project.