Bash Handling the system prompt Using PS4
Example
PS4 is displayes when bash is in debugging mode.
#!/usr/bin/env bash
# switch on debugging
set -x
# define a stupid_func
stupid_func(){
echo I am line 1 of stupid_func
echo I am line 2 of stupid_func
}
# setting the PS4 "DEBUG" prompt
export PS4='\nDEBUG level:$SHLVL subshell-level: $BASH_SUBSHELL \nsource-file:${BASH_SOURCE} line#:${LINENO} function:${FUNCNAME[0]:+${FUNCNAME[0]}(): }\nstatement: '
# a normal statement
echo something
# function call
stupid_func
# a pipeline of commands running in a subshell
( ls -l | grep 'x' )
