issues in bash found while creating command result display

[Paul Wise]

Hi folks,

I wanted a way in bash to print the status of the last command I ran,
including information about each command in a pipe and about signals.

I noticed that bash does not have the ability to display a command
result, so I came up with the attached prompt configuration.

I am hoping that folks here are interested in fixing the things that I
found that I had to workaround:

 * The command number variable $# is not available at the time that the
   PROMPT_COMMAND is run, only when $PS1 is evaluated.
 * There isn't an easy way to detect no command run yet, syntax errors,
   Ctrl+C, Enter etc versus a command being run and exiting
 * Sometimes PIPESTATUS isn't reset even though $? has been reset

I am hoping that folks here have suggestions or fixes for the
things that I found I wasn't able to do:

 * Determine if a command exited normally or due to a signal, even if
   it exited normally with an exit code greater than 128.
 * Have the PIPESTATUS be correct after a Ctrl+Z.
 * Differentiate between Ctrl+C Ctrl+C and Ctrl+C Enter.
 * Disable the status display after tab completion output.
 * Disable the status on the first line of the terminal after using the
   the terminal clearing functionality of GNOME Terminal.

I am hoping that folks here are interested in adding native support for
displaying command status, possibly like this:

 * a PS5 variable that would be evaluated and displayed before the
   display of the PS1 prompt and after every exit of a command or
   Ctrl+C/Ctrl+Z/etc but not after syntax errors
 * a STATUS_COMMAND variable that would be run before evaluation of the
   PS5 variable to support customising it dynamically

-- 
bye,
pabs

https://bonedaddy.net/pabs3/

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