different terminal emulators use different escape codes

terminal emulator 1: if you print out ESC[2J I’ll clear the screen!

terminal emulator 2: for me it’s ESC[HESC[J!

your system has a database called “terminfo” with escape codes in it

how if plays out when you press Ctrl+L to clear the screen:

program, with a little heart over it, thinking:
ah, she wants fo clear the screen! I’ll look up how to do that in the terminfo database…

(on my machine, the database is in /usr/share/terminfo)

program: ESC[HESC[J

terminal emulator, thinking: ok, clearing the screen!

how programs know what terminal you’re using: TERM

your terminal emulator sets the TERM environment variable when it starts

fun fact: terminal emulators often say they’re “xterm-256color” even if they’re not

this can break when SSHing into an old system with a new terminal emulator

(in a VERY annoying way)

happy little stick fiture: I am using ghostty

program, with a little heart over it: NOPE never heard of it

some ways to fix TERM

• install the terminfo file for your terminal emulator on the system
• use a different terminal emulator
• just set TERM=xterm-256color, it’ll often sort of work