Why does kitty run bash (my user shell) with the --posix parameter?

[Filip62]

Hello.

I was scrolling through htop and noticed that kitty starts bash --posix instead of just pure bash for some reason.

In my config I haven't changed the shell option, it looks like the default shell .

In /etc/passwd I have filip:x:1000:1000::/home/filip:/bin/bash

Alacritty and xterm with default settings open normal bash.

I'm not sure what's going on. Any suggestions are appreciated, thank You.

Kitty 0.24.4, Arch linux, bspwm.

[page-down]

kitty provides shell integration without modifying rc files by running bash POSIX mode.
POSIX mode will be disabled after running, so there is nothing to worry about.

https://sw.kovidgoyal.net/kitty/shell-integration/#how-it-works

[Filip62]

I see, thanks.

[infogrind]

POSIX mode will be disabled after running, so there is nothing to worry about.

The documentation at https://sw.kovidgoyal.net/kitty/shell-integration/#how-it-works says

The loading of the startup files is done by the integration script, after disabling POSIX mode. From the perspective of those scripts there should be no difference to running vanilla bash.

That is not what I observe. In my .profile, I am sourcing some scripts to enable bash auto completion. Some of these use bash's <( ) syntax. When starting kitty, I get the following error:

-bash: /Library/GoogleCorpSupport/srcfs/shell_completion/p4: line 25: syntax error near unexpected token `<'
-bash: /Library/GoogleCorpSupport/srcfs/shell_completion/p4: line 25: `    <( ... `

The same error doesn't occur if I open my normal Mac OS terminal.

I can also reproduce the issue simply by starting kitty and typing

echo <(ls)

Actual output:

-bash: syntax error near unexpected token `('

Expected output: something like

/dev/fd/63

When I explicity start a new bash instance (without the --posix flag), the command succeeds.

I am running kitty 0.25.2 on Mac OS Monterey 12.4.

[kovidgoyal]

On Mon, Jun 20, 2022 at 07:40:30AM -0700, Marius Kleiner wrote: That is not what I observe. In my `.profile`, I am sourcing some scripts to enable bash auto completion. Some of these use bash's `<( )` syntax. When starting kitty, I get the following error: ``` -bash: /Library/GoogleCorpSupport/srcfs/shell_completion/p4: line 25: syntax error near unexpected token `<' -bash: /Library/GoogleCorpSupport/srcfs/shell_completion/p4: line 25: ` <( ... ` ``` The same error doesn't occur if I open my normal Mac OS terminal. I can also reproduce the issue simply by starting kitty and typing ``` echo <(ls) ``` Actual output: ``` -bash: syntax error near unexpected token `(' ``` Expected output: something like ``` /dev/fd/63 ``` When I explicity start a new bash instance (without the `--posix` flag), the command succeeds. I am running kitty 0.25.2 on Mac OS Monterey 12.4.

Does not reproduce for me. kitty --config=NONE -o shell=bash echo <(ls) /dev/fd/63 I am guessing you have multiple bashes on your system and a different one is being executed from the one you expect.

[infogrind]

Thanks Kovid for replying so quickly (I got to love Kitty within just a single weekend 😍).

kitty --config=NONE -o shell=bash

Do I have to configure in some way how to start Kitty? All I did was download the DMG from the Github releases page and run it from the Applications folder, nothing more.

I am guessing you have multiple bashes on your system and a different
one is being executed from the one you expect.

I tried to validate this hypothesis. First by getting the PID of the running bash instance:

~$ ps
  PID TTY           TIME CMD
 1558 ttys001    0:00.03 -bash --posix

And then applying this method to find the executable:

lsof -n | grep 1558 | grep ' txt'

This gives me

bash       1558 m*******  txt       REG                1,4    1326576 1152921500312779617 /bin/bash

I then did the same using the default Mac OS Terminal.app (after completely closing/quitting Kitty). There, I see for once that the --posix flag is not there:

$ ps
  PID TTY           TIME CMD
 2721 ttys000    0:00.02 -bash

And then

$ lsof -n | grep 2721 | grep ' txt'
bash       2721 m*******  txt       REG                1,4    1326576 1152921500312779617 /bin/bash

From this it looks like they both use the same binary.

[kovidgoyal]

On Mon, Jun 20, 2022 at 08:45:59AM -0700, Marius Kleiner wrote: Thanks Kovid for replying so quickly (I got to love Kitty within just a single weekend 😍). > kitty --config=NONE -o shell=bash Do I have to configure in some way how to start Kitty? All I did was download the DMG from the Github releases page and run it from the Applications folder, nothing more.

That is just a way of launching kitty with no config and shell set to bash to aid reproduction.

> I am guessing you have multiple bashes on your system and a different one is being executed from the one you expect. I tried to validate this hypothesis. First by getting the PID of the running bash instance: ``` ~$ ps PID TTY TIME CMD 1558 ttys001 0:00.03 -bash --posix ```

/bin/bash on macOS is limited to version 3.2 and does not support a whole bunch of things. If you are really using that, then I suggest you turn off shell_integration in kitty.conf and you will be fine.

[infogrind]

I suppose you have a point. And indeed, I did not plan to use Kitty with Bash. Using it with Fish now, and everything is OK.

Thanks again Kovid!

[alper]

Just for your reference, this is causing an issue say here: starship/starship#5382

[kovidgoyal]

No, it isn't. Startup files are sourced with POSIX mode disabled, as documented.