Mdthbs

Sums of binomial coefficients weighted by incomplete gamma

Unconventional examples of mathematical modelling

Help, I cannot decide when to start the story

How can I find an old paper when the usual methods fail?

The more + the + comparative degree

Why did IBM make the PC BIOS source code public?

Adding things to bunches of things vs multiplication

Why won't the Republicans use a superdelegate system like the DNC in their nomination process?

Why aren't rockets built with truss structures inside their fuel & oxidizer tanks to increase structural strength?

Why does Japan use the same type of AC power outlet as the US?

How to get locks that are keyed alike?

What evidence points to a long ō in the first syllable of nōscō's present-tense form?

Telephone number in spoken words

How to programatically get all linked items for a given Sitecore item?

Number in overlapping range

Is this bar slide trick shown on Cheers real or a visual effect?

What is axle tramp?

List, map function based on a condition

Suspension compromise for urban use

Would the USA be eligible to join the European Union?

How can I communicate my issues with a potential date's pushy behavior?

What is the hottest thing in the universe?

Output the list of musical notes

What would cause a nuclear power plant to break down after 2000 years, but not sooner?

In GNU readline, How to change Alt key to Meta, instead of being ESC?

What is bash's meta key?How to change readline's/bash's meta key?How can I change readline settings on keypress?readline: How do I change keymaps from `emacs` to `vi-command` with a binding?Shortcut for line continuation (escaped newline) actionHow to Set Readline key bindings in both vi-command and vi-insert modes

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ margin-bottom:0;
}

1

In GNU readline manual, it says the left Alt is usually Meta:

The Meta key is labeled ALT on many keyboards. On keyboards with two keys labeled ALT (usually to either side of the space bar), the ALT on the left side is generally set to work as a Meta key.

But by experiment, I think the left Alt is actually ESC, rather than Meta. That's because, given the following inputrc configuration:

"eB": vi-bWord

Pressing AltShiftb works as expected.

However if I change the key binding to the following:

"M-B": vi-bWord

Pressing AltShiftb does nothing.

I'm wondering why Alt is actually ESC instead of Meta? How to change Alt to act as Meta key?

readline

share|improve this question

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  unix.stackexchange.com/a/266490/70524
  
  – muru
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try in a shell started as INPUTRC=/dev/null LC_CTYPE=C bash --norc. I don't think that M- works with utf-8 locales (haven't tried too much either, though ;-)).
  
  – mosvy
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  basically, readline should recognize ESC as a synonym for the meta-prefix. "eB" and "M-B" should be synonymous.
  
  – mosvy
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @mosvy Just tried LC_CTYPE=C trick. This is interesting -- in UTF-8 locales, bind -p shows all e ESC prefixed key bindings, while in C locale they are just M- prefixed as advertised in the manual. Seems Meta has some other uses in non-C locales? Combining several clues presented to me, including the answer linked by @muru (which I do not understand 100%) and readline variables like input-meta, output-meta, convert-meta, I vaguely think Meta is not normally used because somehow M- prefixed keys conflict with multi-byte characters??
  
  – Naitree
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can ignore (for now) the high-bit/metaSendsEscape mess -- your terminal is clearly sending ESC when you press ALT (you can make that sure by running cat and pressing ALT-p: it should print ^[p). The problem is why "eB" and "M-B" are only considered synonymous in bindings when LC_CTYPE is C -- I haven't got an answer for that, yet.
  
  – mosvy
  yesterday
  
  
  

  
  
  
  

add a comment | 

1

In GNU readline manual, it says the left Alt is usually Meta:

The Meta key is labeled ALT on many keyboards. On keyboards with two keys labeled ALT (usually to either side of the space bar), the ALT on the left side is generally set to work as a Meta key.

But by experiment, I think the left Alt is actually ESC, rather than Meta. That's because, given the following inputrc configuration:

"eB": vi-bWord

Pressing AltShiftb works as expected.

However if I change the key binding to the following:

"M-B": vi-bWord

Pressing AltShiftb does nothing.

I'm wondering why Alt is actually ESC instead of Meta? How to change Alt to act as Meta key?

readline

share|improve this question

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  unix.stackexchange.com/a/266490/70524
  
  – muru
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try in a shell started as INPUTRC=/dev/null LC_CTYPE=C bash --norc. I don't think that M- works with utf-8 locales (haven't tried too much either, though ;-)).
  
  – mosvy
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  basically, readline should recognize ESC as a synonym for the meta-prefix. "eB" and "M-B" should be synonymous.
  
  – mosvy
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @mosvy Just tried LC_CTYPE=C trick. This is interesting -- in UTF-8 locales, bind -p shows all e ESC prefixed key bindings, while in C locale they are just M- prefixed as advertised in the manual. Seems Meta has some other uses in non-C locales? Combining several clues presented to me, including the answer linked by @muru (which I do not understand 100%) and readline variables like input-meta, output-meta, convert-meta, I vaguely think Meta is not normally used because somehow M- prefixed keys conflict with multi-byte characters??
  
  – Naitree
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You can ignore (for now) the high-bit/metaSendsEscape mess -- your terminal is clearly sending ESC when you press ALT (you can make that sure by running cat and pressing ALT-p: it should print ^[p). The problem is why "eB" and "M-B" are only considered synonymous in bindings when LC_CTYPE is C -- I haven't got an answer for that, yet.
  
  – mosvy
  yesterday
  
  
  

  
  
  
  

add a comment | 

In GNU readline manual, it says the left Alt is usually Meta:

The Meta key is labeled ALT on many keyboards. On keyboards with two keys labeled ALT (usually to either side of the space bar), the ALT on the left side is generally set to work as a Meta key.

But by experiment, I think the left Alt is actually ESC, rather than Meta. That's because, given the following inputrc configuration:

"eB": vi-bWord

Pressing AltShiftb works as expected.

However if I change the key binding to the following:

"M-B": vi-bWord

Pressing AltShiftb does nothing.

I'm wondering why Alt is actually ESC instead of Meta? How to change Alt to act as Meta key?

readline

share|improve this question

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges

"eB": vi-bWord

"M-B": vi-bWord

share|improve this question

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges

share|improve this question

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges

asked yesterday

NaitreeNaitree

33211 gold badge22 silver badges1212 bronze badges