Running the script it has issues using mysqldump on my MacOs Sierra though running it from the terminal using mysqldump works just fine. Here is what I get

./sync-db-from-prod.sh
Do you solemnly swear that you have had fewer than 2 alcoholic beverages in the last hour and that you would really like to reset your development database and pull the latest from production? [y/N] y
Success: Database reset.
/usr/bin/env: ‘mysqldump’: No such file or directory
Success: Imported from 'sql-dump-production.sql'.
Error: The site you have requested is not installed.
Run `wp core install`.

The wp cli aliases are already defined in wp-cli.yml - it would reduce the amount of config and
the necessity keeping it in sync when trellis-sync also uses the config in wp-cli.yml.

Wouldn't it be a nice addition to have this tool as a WP CLI package,
also installable using wp package install ?

The -L switch let rsync follow symlinks/Junctions (in WSL/Bash on Windows).
This can be helpful - wouldn't it make sense to add this switch to the script?

Running the script returns:

scripts/sync-all.sh: 25: scripts/sync-all.sh: Syntax error: "(" unexpected (expecting "then")

Transferring the database dump and replacements work well,
but transferring the uploads/ folder between the two servers results in this error message:

[...]
Success: Made 16 replacements.
The source and destination cannot both be remote.
rsync error: syntax or usage error (code 1) at main.c(1279) [Receiver=3.1.1]

This script works really nice for transferring data between WordPress installations.
Is there also an example for using this script for backing up to tar/gzip,
ideally incrementally (important for the uploads files), with date/time stamps?
I plan to run the script in regular intervals for automated site backups
(from production site which holds the authoritative data).

As the Wordpress CLI page suggests in the examples of a way to have multisite compatibility. I tweaked the sync-all.sh script for this and to also ask if the uploads folder should update. Also shortened the options names 👍
It does not seem to be working... however 👎
This is what I have so far:

#!/bin/bash

DEVDIR="web/app/uploads/"
DEVSITE="https://example.dev"

PRODDIR="[email protected]:/srv/www/example.com/current/web/app/uploads"
PRODSITE="https://example.com"

STAGDIR="[email protected]:/srv/www/example.com/current/web/app/uploads"
STAGSITE="https://staging.example.com"

FROM=$1
TO=$2

case "$1-$2" in
  dev-prod) DIR="up";  FROMSITE=$DEVSITE;  FROMDIR=$DEVDIR;  TOSITE=$PRODSITE; TODIR=$PRODDIR; ;;
  dev-stage)    DIR="up"   FROMSITE=$DEVSITE;  FROMDIR=$DEVDIR;  TOSITE=$STAGSITE; TODIR=$STAGDIR; ;;
  prod-dev) DIR="down" FROMSITE=$PRODSITE; FROMDIR=$PRODDIR; TOSITE=$DEVSITE;  TODIR=$DEVDIR; ;;
  stage-dev)    DIR="down" FROMSITE=$STAGSITE; FROMDIR=$STAGDIR; TOSITE=$DEVSITE;  TODIR=$DEVDIR; ;;
  *) echo "usage: $0 dev prod | dev stage | prod dev | prod stage" && exit 1 ;;
esac

read -r -p "Reset the $TO database and sync $DIR from $FROM? [y/N] " response
read -r -p "Sync the uploads folder? [y/N] " uploads

cd ../ &&
if [[ "$response" =~ ^([yY][eE][sS]|[yY])$ ]]; then
  wp "@$TO" db export $TO.sql
  wp "@$TO" db reset --yes
  wp "@$FROM" db export $FROM.sql
  if $(wp "@$FROM" core is-installed --network); then
    echo "multisite"
    wp "@$FROM" search-replace '$FROMSITE' '$TOSITE' --recurse-objects --skip-columns=guid --network --export | wp "@$TO" db import -
  else
    wp "@$FROM" search-replace '$FROMSITE' '$TOSITE' --recurse-objects --skip-columns=guid --export | wp "@$TO" db import -
  fi
fi
if [[ "$uploads" =~ ^([yY][eE][sS]|[yY])$ ]]; then
  rsync -az --progress "$FROMDIR" "$TODIR"
fi

When I use this to sync from dev to stage, I get a redirect loop when I try to load the staging page. If I, however, just do a manual search and replace of the raw sql (playing with fire, I know) file it seems to work.

Error when running sync-all.sh

[user@host scripts]$ bash sync-all.sh dev stage
Reset the stage database and sync up from dev? [y/N] y
Sync the uploads folder? [y/N] y
Success: Exported to 'stage-backup.sql'.
Success: Database reset.
Error: Cannot connect over SSH using provided configuration.
sending incremental file list

Result
Strangely the demo file I placed in the /web/app/uploads folder did successfully get uploaded to the stage environment. But when I removed the demo file and tried to run that same command again, the demo file remained in the stage environment as if it was not updating. It can send the file but cannot delete the file so it doesn't seem to be syncing.

Debug attempts:
I also checked the user 'web' and was able to successfully ssh into my remote server.

.

Forgive my ignorance, but Composer is abstract to me and I'm relatively new to it.

How do I add this to my ./site/composer.json file?