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Life Line

Pretty Prompts

When giving recently, I got a question about my terminal prompt. Besides the standard user@host:path I show a whole bunch of other information too:

The first part is the GIT status and git branch. The colour indicates the state of the branch. Red means changes to files, yellow means untracked files, and green means everything is up-to-date.

The second part gives information about the PHP runtime and environment. It has the PHP version (7.4.3) and then four letters, and a number. The letters can be either green (active) or red (inactive), and in order they are:

A

This is active when the environment variable USE_ZEND_ALLOC is set to 0. With this environment variable set, PHP disables its internal memory manager so that tools like Valgrind can more accurately report memory issues with PHP and its extensions.

U

This letter is active when the environment variable ZEND_DONT_UNLOAD_MODULES is set to 1. With that variable set, PHP will not unload shared extensions at the end of the request, resulting in better memory reporting with Valgrind again.

D

Whether the PHP version that is active is compiled in Debugging mode, which is essential for working on extensions, such as Xdebug.

N/Z

Whether the PHP binary is compiled without thread safety (N) or with (Z). In general, you don't really thread safety on, but I test Xdebug with it as it's still used quite a bit.

Following the numbers is an indicator where PHP is compiled in 64 bit mode (⁶⁴) or 32 bit mode (₃₂). For production environments you usually use 64 bit mode, but I also still test Xdebug in 32 bit mode.

Following the GIT and PHP status is the version of Xdebug that is currently loaded.

As I switch between branches and configurations, all these indicators together assist me by telling me exactly what's going on—and making me less confused.


I make this work by hacking the bash prompt. Instead of just using the path, I also add these extra modifiers by changing PS1:

function _prompt_command() {
        PS1='\[\e[48;5;234m\]\[$(printf " %.0s" $(seq 1 $(tput cols)))\r\]\[\e[0m\]'"`_git_prompt``_php_prompt`\n"'${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
}
PROMPT_COMMAND=_prompt_command

_git_prompt command does all the GIT status things, and _php_prompt the PHP and Xdebug indicators. Both commands run commands to find out the status. _php_prompt starts with:

function _php_prompt() {
        local php_v="`php -n -v 2>&1`"
        local php_status="`echo "${php_v}" | head -n 1 | cut -d " " -f 2`"
        local php_zts="`echo "${php_v}" | head -n 1 | grep ZTS`"
        local php_debug="`echo "${php_v}" | head -n 1 | grep DEBUG`"
        local php_64="`php -n -r 'echo PHP_INT_SIZE == 4 ? "32" : "64";' 2>&1`"
        local flag1="`set | egrep '^(USE_ZEND_ALLOC=0)'`"
        local flag2="`set | egrep '^(ZEND_DONT_UNLOAD_MODULES=1)'`"

And then code further on formats these, selects colours, and then echos the collated information by using ANSI terminal codes. Displaying the GIT portion is done with:

echo '\[\e[0;48;5;239;'"$ansi"'m\] '"${symbol}"' \[\e[39;48;5;239m\]'"$branch"'\[\e[39m\] \[\e[0m\]'

Where $ansi is the colour for the symbol, and $branch the GIT branch name.

I've created a Gist with the whole section, which you can copy and paste into your .bashrc if you feel so inclined. If you have any suggestions and/or comments, I'm more than happy to hear them.

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