Retry logic in bash (for ssh / scp)

retry.bash

#!/bin/bash
set -o nounset
set -o errexit
set -o pipefail

declare -r max=4
declare i=0

function wrap() {
	local cmd=$1 ; shift
	retry $cmd "$@"
	set -o errexit
}

function retry() {
	set +o errexit
	local cmd=$1 ; shift
	$cmd "$@"
	if [ $? -ne 0 -a $i -lt $max ] ; then
		i=$(($i+1))
		echo "Retrying"
		sleep $((1+$i*$i*5))
		retry $cmd "$@"
	fi
}

wrap "$@"

It's great. Thanks @florianleibert!

The only problem that I had is that I wanted the exit status of the command to be different to zero when the retry fails. I've forked the gist and added this modification if you want to have a look.

https://gist.github.com/txominpelu/a8e886cf55e2c26d55c8

Useful little script.

I've made changes based upon both of the above, so if it fails with Code 6 initially (missing local file), it'll not continue retrying, and it'll similarly pass out any other non-zero failure codes after the appropriate retry length.

https://gist.github.com/leezer3/7f5add40ddb7b16654d2378e292bb28b