Re: BASH_BUILTINS(1) | 'man bash_builtins' | Manual not found

[Greg Wooledge]

On Thu, Sep 30, 2021 at 01:56:45PM +0200, Andreas Schwab wrote:
> On Sep 30 2021, Greg Wooledge wrote:
> 
> > No, they probably have a /usr/share/man/man1/alias.1.gz -> 
> > bash-builtins.1.gz
> > symlink or something, set up by their OS vendor.
> 
> See the comment in doc/builtins.1:
> 
> .\" This is a hack to force bash builtins into the whatis database
> .\" and to get the list of builtins to come up with the man command.
> 
> This happens automagically.

unicorn:~$ locate builtins.7
[...]
/etc/alternatives/builtins.7.gz
/usr/share/man/man7/bash-builtins.7.gz
/usr/share/man/man7/builtins.7.gz
/var/lib/dpkg/alternatives/builtins.7.gz
unicorn:~$ ls -l /usr/share/man/man7/builtins.7.gz 
lrwxrwxrwx 1 root root 31 Aug  5 07:09 /usr/share/man/man7/builtins.7.gz -> 
/etc/alternatives/builtins.7.gz
unicorn:~$ ls -l /etc/alternatives/builtins.7.gz
lrwxrwxrwx 1 root root 38 Aug  5 07:09 /etc/alternatives/builtins.7.gz -> 
/usr/share/man/man7/bash-builtins.7.gz
unicorn:~$ ls -l /usr/share/man/man7/bash-builtins.7.gz
-rw-r--r-- 1 root root 508 Aug  4 16:25 /usr/share/man/man7/bash-builtins.7.gz


unicorn:~$ man mapfile
No manual entry for mapfile
unicorn:~$ man complete | head -n1
No manual entry for complete
unicorn:~$ man alias | head -n1
ALIAS(1POSIX)              POSIX Programmer's Manual             ALIAS(1POSIX)
unicorn:~$ man for | head -n1
for(n)                       Tcl Built-In Commands                      for(n)


Again, all of this stuff is OS-specific.  Or in some cases, even single-
system-specific.

It's also possibly worth pointing out that the "builtins.7" provided
by Debian 11 contains a synopsis from bash 2.05b, listing a set of
builtin commands that's *vastly* out of date.  But the actual content
provided by "bash-builtins.7" is newer, and includes builtins like
mapfile, which are not listed in the synopsis.