su

#!/data/data/com.termux/files/usr/bin/env bash
# Normal interactive su wrapper
# Reads normal rc/profile, fake $0, PS1 (~ + $PREFIX->/), -c, pipes

# -------------------------------
# 1️⃣ Fake $0 for echo
echo_func() {
    if [[ "$1" == "\$0" ]]; then
        printf "su\n"
    else
        command echo "$@"
    fi
}
alias echo='echo_func'

# -------------------------------
# 2️⃣ PS1 builder function
build_prompt() {
    local dir="${PWD/#$PREFIX//}"   # Replace $PREFIX prefix with /
    if [[ "$dir" == "$HOME"* ]]; then
        dir="~${dir#$HOME}"        # Replace home with ~
    fi
    PS1=" $dir # "
}
PROMPT_COMMAND=build_prompt

# -------------------------------
# 3️⃣ Pipe input
if [ ! -t 0 ]; then
    bash -s
    exit
fi

# -------------------------------
# 4️⃣ -c command
if [ "$1" = "-c" ] && [ $# -ge 2 ]; then
    shift
    bash -c "$*"
    exit
fi

# -------------------------------
# 5️⃣ Default interactive shell
exec bash