sshforce = ssh wrapper that doesn't care about fingerprint changes (add -Z to retry connecting indefinitely)

sshforce

#!/usr/bin/env bash
set -euo pipefail

if [ "$#" -eq 0 ]; then
    echo "Usage: sshforce [-Z] [ssh flags] <hostname> [ssh flags]" >&2
    exit 1
fi

# ssh short flags that consume the following argument as a value
value_flags='BbcDEeFIiJLlmOopQRSWw'

hostname=""
port=""
retry=0
filtered_args=()
args=("$@")
i=0
while [ $i -lt ${#args[@]} ]; do
    arg="${args[$i]}"
    if [[ "$arg" == -- ]]; then
        filtered_args+=("$arg")
        i=$((i + 1))
        if [ $i -lt ${#args[@]} ] && [ -z "$hostname" ]; then
            hostname="${args[$i]}"
        fi
        while [ $i -lt ${#args[@]} ]; do
            filtered_args+=("${args[$i]}")
            i=$((i + 1))
        done
        break
    fi
    if [[ "$arg" == "-Z" ]]; then
        retry=1
        i=$((i + 1))
        continue
    fi
    if [[ "$arg" == -* ]]; then
        if [ ${#arg} -eq 2 ] && [[ "$value_flags" == *"${arg:1:1}"* ]]; then
            if [ "$arg" = "-p" ] && [ $((i + 1)) -lt ${#args[@]} ]; then
                port="${args[$((i + 1))]}"
            fi
            filtered_args+=("$arg")
            if [ $((i + 1)) -lt ${#args[@]} ]; then
                filtered_args+=("${args[$((i + 1))]}")
            fi
            i=$((i + 2))
            continue
        fi
        filtered_args+=("$arg")
        i=$((i + 1))
        continue
    fi
    if [ -z "$hostname" ]; then
        hostname="$arg"
    fi
    filtered_args+=("$arg")
    i=$((i + 1))
done

if [ -z "$hostname" ]; then
    echo "sshforce: could not locate hostname in args" >&2
    exit 1
fi

# strip user@ prefix for the known_hosts lookup
host_only="${hostname#*@}"

if [ -n "$port" ] && [ "$port" != "22" ]; then
    ssh-keygen -R "[$host_only]:$port"
else
    ssh-keygen -R "$host_only"
fi

if [ "$retry" -eq 0 ]; then
    exec ssh -o StrictHostKeyChecking=accept-new "${filtered_args[@]}"
fi

while true; do
    rc=0
    ssh -o StrictHostKeyChecking=accept-new "${filtered_args[@]}" || rc=$?
    # ssh returns 255 on connection failure; other codes come from the remote side
    if [ "$rc" -ne 255 ]; then
        exit "$rc"
    fi
    sleep 1
done