You can simplify things a bit by putting command right in the test and doing increments a bit differently. Otherwise the script looks fine:

NEXT_WAIT_TIME=0until [ $NEXT_WAIT_TIME -eq 5 ] || command; do    sleep $(( NEXT_WAIT_TIME++ ))done[ $NEXT_WAIT_TIME -lt 5 ]

One line and shortest, and maybe the best approach:

timeout 12h bash -c 'until ssh root@mynewvm; do sleep 10; done'

Credited by http://jeromebelleman.gitlab.io/posts/devops/until/

retry fuction is from:

http://fahdshariff.blogspot.com/2014/02/retrying-commands-in-shell-scripts.html

#!/bin/bash# Retries a command on failure.# $1 - the max number of attempts# $2... - the command to runretry() {    local -r -i max_attempts="$1"; shift    local -r cmd="$@"    local -i attempt_num=1    until $cmd    do        if (( attempt_num == max_attempts ))        then            echo "Attempt $attempt_num failed and there are no more attempts left!"            return 1        else            echo "Attempt $attempt_num failed! Trying again in $attempt_num seconds..."            sleep $(( attempt_num++ ))        fi    done}# example usage:retry 5 ls -ltr foo

if you want to retry an function in your script, you should do like this:

# example usage:foo(){   #whatever you want do.}declare -fxr fooretry 3 timeout 60 bash -ce 'foo'