lfs-book-zh_CN/appendixa/bash-desc.xml

<sect2><title>Short descriptions</title>

<para><command>bash</command> is a widely-used command interpreter. It
performs all kinds of expansions and substitutions on a given command line
before executing it, thus making this interpreter a powerful tool.</para>

<para><command>bashbug</command> is a shell script to help the user
compose and mail bug reports concerning bash in a standard format.</para>

<para><command>sh</command> is a symlink to the bash program. When invoked
as sh, bash tries to mimic the startup behavior of historical versions of sh as
closely as possible, while conforming to the POSIX standard as well.</para>

</sect2>