From this guide to Bash completion we learn that in order for Bash to perform auto-completion one must perform . /etc/etc/bash_completion.d/foobar (note the space after .) in order for Bash completion to work.$ /etc/bash_completion.d/sshbash: /etc/bash_completion.d/ssh: Permission denied$ . /etc/bash_completion.d/ssh$ ls -l /etc/bash_completion.d | grep ssh-rw-r--r-- 1 root root   297 Jan 28 18:04 sshIs . a shortcut for the source command? If not, then what is it? It is impossible to google for, man source returns nothing, and apropos source and info source give so much irrelevant information that I cannot tell if what I'm looking for is in there. How might I even begin to RTFM to find the answer to this question myself?
What does `. /path/command` do? (Space after dot, absolute path)
bash
Yes . is identical to the source function. As always the first reference is the man bash manual page where you can confirm your initial guess by searching for / source...shell function or script executed with . or source...is the first reference, but a bit further you find a section Shell Builtin Commands . filename [arguments]source filename [arguments]  Read and execute commands from filename in the current shell  environment and return the exit status of the last command executed  from filename. If filename does not contain a slash, file names in  PATH are used to find the directory containing filename. The file  searched for in PATH need not be executable. When bash is not in posix  mode, the current directory is searched if no file is found in PATH.  If the sourcepath option to the shopt builtin command is turned off,  the PATH is not searched. If any arguments are supplied, they become  the positional parameters when filename is executed. Otherwise the  positional parameters are unchanged. The return status is the status  of the last command exited within the script (0 if no commands are  executed), and false if filename is not found or cannot be read.That fact it is a bash builtin function is the reason source doesn't come with its own man page, which is why apropos failed. 