fish shell: Prompt changing to '>' - fish

Question

I recently switched to fish and modified one of the prompts available from fish_config to look like this.
function fish_greeting
fortune
end
function fish_prompt
echo
set -l retc brblack
test $status = 0; and set retc bryellow
set -q __fish_git_prompt_showupstream
or set -g __fish_git_prompt_showupstream auto
function _nim_prompt_wrapper
set retc $argv[1]
set cust $argv[4]
set field_name $argv[2]
set field_value $argv[3]
set_color normal
set_color $retc
echo
echo -n ' ├─'
echo -n '[ '
set_color normal
test -n $field_name
and echo -n $field_name
set_color -o brblack
echo -n ' ▶ '
set_color $retc
set_color $cust
echo -n $field_value
set_color $retc
echo -n ' ]'
end
set_color $retc
echo -n '─┬─'
echo -n '[ '
set_color -o red
echo -n (prompt_hostname)
echo -n ': '
if test "$USER" = root -o "$USER" = toor
set_color -o brred
else
set_color -o brwhite
end
echo -n $USER
set_color -o brblack
echo -n ' ▶ '
set_color -o brcyan
echo -n (pwd)
set_color $retc
echo -n ' ]'
# Virtual Environment
set -q VIRTUAL_ENV_DISABLE_PROMPT
or set -g VIRTUAL_ENV_DISABLE_PROMPT true
set -q VIRTUAL_ENV
and _nim_prompt_wrapper $retc '🐍 ' (basename "$VIRTUAL_ENV") cyan
# git
set prompt_git (fish_git_prompt | string trim -c ' ()')
test -n "$prompt_git"
and _nim_prompt_wrapper $retc (basename -s .git (git config --get remote.origin.url) 2> /dev/null) $prompt_git
# New line
echo
# Background jobs
set_color normal
for job in (jobs)
set_color $retc
echo -n ' │ '
set_color brown
echo $job
end
set_color normal
set_color $retc
echo -n ' ╰─> '
set_color normal
end
The general layout of my prompt:
─┬─[ hostname: user ▶ pwd ]
╰─> _
And blow is what I want instead of >:
─┬─[ hostname: user ]
├─[ pwd ]
╰─> _
OR
─┬─[ hostname: username ]
├─⎡ as_much_as_possible ⎤
├─⎣ the_rest_of_PWD ⎦
╰─> _
But, when $PWD is longer than the window's column size, the whole prompt is just >. I feel that using $COLUMNS should work, but I don't know how I can check the length of pwd before echoing it.
I DO NOT WANT TO USE prompt_pwd.
Thanks in advance! ;)

Answer 1

You can store whatever you want in a variable and then check it, modify it however you want and then echo it.
Here's a rough sketch:
set -l firstline '─┬─[' (prompt_hostname): $USER ▶ $PWD ']'
set -l secondline
if test (string length -- "$firstline") -gt $COLUMNS
# move $PWD to the second line
set firstline '─┬─[' (prompt_hostname): $USER ']'
set secondline '├─[' $PWD ']'
end
echo $firstline
echo $secondline
I DO NOT WANT TO USE prompt_pwd.
You very possibly do. It handles replacing $HOME with ~ (which saves quite a few columns) and does shortening to $fish_prompt_pwd_dir_length characters, or no shortening other than ~ if that's set to 0.
You can even adapt the shortening to $COLUMNS. From my prompt:
# Shorten pwd if prompt is too long
set -l pwd (prompt_pwd)
# 0 means unshortened
for i in $fish_prompt_pwd_dir_length 0 10 9 8 7 6 5 4 3 2 1
set pwd (fish_prompt_pwd_dir_length=$i prompt_pwd)
set -l len (string length -- $prompt_host_nocolor$pwd$last_status$delim' ')
if test $len -lt $COLUMNS
break
end
end