May 2026

windows terminal, bash, text wrapping incorrectly over color prompt

Are long command lines wrapping over your bash prompt? At work I have been using windows terminal and this terminal is much less robust than xterm. It's technically not a windows terminal fault but rather a bash problem but xterm seems to have a better a better error handling and it does not mess up the screen as severely as on windows terminal.

What is happening is this: you type a long command line and instead of the text wrapping to the next line you see it overwriting your command prompt. When you recall a command from the history then things are messed up too and you see a mixture of the last command as well as the history you are stepping through.

It turns out that the PS1 bash prompt itself is causing the lines on the terminal to wrap incorrectly. The problem does not happen with a plain ascii prompt such as

PS1='[\h \W]\$'

The lines start to wrap incorrectly only when you use ansi color codes in the prompt. It happens because Bash needs to know which characters in your PS1 are non-printing. The ansi color codes are characters in the PS1 prompt but they don't show on the screen. They just change the color. This causes an incorrect calculation of the line length and therefore incorrect line wrapping.

The solution is to enclose non printing characters between \[ and \]. This sequence tells bash to not count these characters when calculating the line length. This fixes the incorrect line wrapping on the screen.

A PS1 prompt that works is:
PS1='[\[\033[01;34m\]\h\[\033[00m\] \W]\$'

The below would be visually the same prompt but it messes up the screen:
PS1='[\033[01;34m\h\033[00m \W]\$'

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