bash-tput

A drop-in replacement for tput in Bash scripts that is extremely limited and opinionated.

Usage

You can use this code in 3 main ways:

1. Copy + Paste

This is the easiest and most straight-forward - just copy and paste the code into your existing Bash script:

tput() {
    ...
}

# your script goes here

2. Source this file

Source the file if it exists in a known-location on your filesystem:

. ./tput

# your script goes here

3. Execute this script directly

You can just run this script directly to test it yourself:

$ ./tput setaf 1; echo hi
hi

NOTE: this completely negates the speed-benefit of calling this from a script but it's great for testing.

Reasoning

This code was originally written for a Bash TUI called Nightfall. In profiling that code it took around ~600 calls to tput to render the initial UI and that ended up being very slow on some systems. Other systems (FreeBSD for example) just didn't work with some of the tput commands not being supported.

I decided to "wrap" tput in a Bash function that would bake-in as much of the functionality I needed and then fork out to the external tput command when needed. This Brought the number of forked tput calls to 0 to draw the UI which sped the program up immensely and resulted in FreeBSD working as well.

Synopsis

tput(1) is a command that offers "Portable Terminal Control" but, in practice, is not very portable. Posix specifies it must exist and support a small number of options but isn't very specific about its usage and command naming.

A number of sources were surveyed to see what kind of usage is out there in the wild:

• tput provided by Linux (via ncurses)
• tput.c on FreeBSD
• tput.c on illumos
• tput usage on MacOS

There is a large number of overlap in both arguments and commands but there are still some differences (notably setaf vs AF on FreeBSD, or the lack of -S and -V support on some operating systems).

Goal

The goal of this project is to provide a drop-in replacement function that can be sourced (or copy and pasted) into existing Bash scripts and they will just reap the benefits of a more uniform tput command for outputting terminal control characters. This will make the scripts execute much faster as well as work across more operating system independent version of tput.

Philosophy

This version of tput should NOT break anything - it should just optimize for the common case of outputting terminal control characters. When this version of tput can NOT do something itself it will instead opt to fork out to the external version of tput found.

Because of this, this version will accept arguments like -T <term> but completely ignore them (unless passed to the external tput command) and instead always opt to output ANSI escape sequences.

References

• https://nightfall.ysap.sh
• https://github.com/dylanaraps/pure-bash-bible?tab=readme-ov-file#escape-sequences
• https://github.com/fidian/ansi
• https://linuxcommand.org/lc3_adv_tput.php
• https://www.gnu.org/software/termutils/manual/termutils-2.0/html_chapter/tput_1.html
• https://pubs.opengroup.org/onlinepubs/009696899/utilities/tput.html

License

MIT License