Getting "complete" and "menu-complete" to work together
I found out that the Bash shell supports a type of autocompletion that is different from the "traditional" autocompletion, where all possibilities get listed on the following line.
With the "traditional" autocompletion, if I type ch and then press the Tab key, I get something like:
$ ch
chacl chgrp chmod chown chvt
But if I add the following line to my /etc/inputrc (which remaps the Tab key to the built-in menu-complete function):
Tab: menu-complete
then the behavior of the shell changes: the word to be completed is replaced "inline" with a single match from the list of possible completions, and if I press the Tab key again, the word gets replaced with the next match.
I found this useful, but I still wanted to keep the traditional autocompletion and have it bound to the key combination Ctrl + Tab. So I added the following line to my /etc/inputrc file, according to what the readline library documentation suggests:
Ctrl-Tab: complete
However, adding this line only seems to make both Tab and Ctrl-Tab call the traditional complete function.
Does anyone know what I am doing wrong?
Thanks in advance!
Answer
To start with, I'm not a massive expert in this area, but I think I can answer your question. First of all, while you are using Bash, Bash is a shell which interprets keyboard commands that it receives from a terminal / console. While you are informing Bash how to react to specific key combinations in the inputrc file, your Terminal determines precisely which character is 'sent' to the Shell before the inputrc file even enters the equation.
Unfortunately, on my system (granted, it's OSX - but I don't think this is strange behaviour when compared to Linux), both Tab and Ctrl-Tab send the same keyboard input to the shell. Infact, both Tab and Ctrl-Tab send a Ctrl-I command to the shell, and indeed, if I enter Ctrl-I when using the terminal, it performs the completion as if I hit Tab.
The software (installed on most Linux systems by default), showkey will tell you what keys the shell is receiving when you press specific keyboard inputs as you push them.
Anyway, my suggestion to you is to use Shift-Tab, which does appear to send it's own key-code to the shell. Shift-Tab on my computer shows up (using showkey) as '<ESC>[Z', which I think is pretty standard across the board. As such, your inputrc file with the following bindings should allow you to use shift-tab instead of ctrl-tab to achieve what you desire:
Tab: menu-complete
"\e[Z": complete
The \e in the second binding represents the escape character, and the [Z are simply the characters as shown using showkey. You can get a similar effect on OSX by simply using cat, running cat from within a terminal and pressing Shift-Tab will show you "^[[Z", where ^[ represents the escape character and the other characters are as before.
I know this doesn't resolve your question precisely, but as I don't think you are able to use Ctrl-Tab as a key combination, without re-mapping Ctrl-Tab to another keybinding within your terminal (more likely to be easier if you are using a GUI terminal), this is likely as close as you can get without significant effort!