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I'd like to add a keybinding to my .inputrc that puts the value of an environment variable, USER, on the command line.

I tried all kinds of escaping but the string $USER is written verbatim to the command line, not the value of that environment variable.

$if mode=vi
  # Keymaps when we are in insert mode
  set keymap vi-insert

  # Insert path before mountpoint
  "C-e": "/run/media/$USER"

Is there a reasonable way to do this with .inputrc or am I better off using other means like .bashrc?

Matthias Braun
  • 8,239
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    Note, if you have a partly typed command with $variables in it, you can have them expanded by calling the readline function shell-expand-line, which you can bind to some character sequence. – meuh May 15 '18 at 18:25
  • Check out a similar question. – meuh May 15 '18 at 18:35

2 Answers2

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User meuh's tip to use shell-expand-line led me to this solution which puts the environment variable's value on the command line:

$if mode=vi
  # Keymaps when we are in insert mode
  set keymap vi-insert

  # Expand variables like ~ and $USER to their values
  "\C-a": shell-expand-line
  # Insert path before mountpoint, then expand the variable
  "\C-e": "/run/media/$USER/\C-a"

Now, pressing Ctrl+e results in /run/media/me/ on the command line.

Matthias Braun
  • 8,239
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Inserting the literal string $USER rather than the expanded value of the USER variable may not make a big difference, as the variable is likely defined with the proper value (assuming a Linux system) and would be expanded by the shell.

This answers an earlier incarnation of the question:

You can not use environment variables in .inputrc.

To incorporate the username of the current user in bash's primary prompt, set PS1 to a value containing the escape sequence \u.

See the section labelled "PROMPTING" in the bash manual.

Kusalananda
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  • Thanks for your answer, Kusalananda! I was thinking of putting text on the command line, not changing the command prompt. I edited the question accordingly. – Matthias Braun May 15 '18 at 17:48
  • @MatthiasBraun Ah, in that case, since $USER is most likely a valid environment variable on Linux systems (other systems use $LOGUSER), then I don't really see a problem with having the literal string $USER inserted. Care to elaborate? – Kusalananda May 15 '18 at 17:50
  • You're right, thinking about it, it's not a big difference between /run/media/$USER/ and /run/media/me/ for my purposes. Path completion works as well using bash on Arch Linux. – Matthias Braun May 15 '18 at 18:30