datediff bash function

Datediff function to return the number of days between two dates.  It's not too robust, but I got it working on MacOS and Linux, mostly to accommodate the differences between GNU Util date and HomeBrew BSD date...

datediff() {
    date --version >> /dev/null 2>&1
    RETVAL=$?
    if [ -e /usr/local/bin/gdate ] && [ $RETVAL -ne 0 ] ;
    then
        DATEBIN=/usr/local/bin/gdate
    else
        DATEBIN=`which date`
    fi

    d1=$($DATEBIN -d "$1" +%s)
    d2=$($DATEBIN -d "$2" +%s)
    echo $(( (d1 - d2) / 86400 )) days
}

GNU date in MacOS

The GNU date utility is provided in the HomeBrew package coreutils as gdate.  Install with HomeBrew.

[~]
scott@bargamac$ HOMEBREW_NO_AUTO_UPDATE=1 brew install coreutils
==> Downloading https://homebrew.bintray.com/bottles/coreutils-8.32.mojave.bottle.tar.gz
==> Downloading from https://akamai.bintray.com/5d/5da6cb9dbc0a8144480dde2fb78eb0a5a1710490afc3697174f7e261ec69763f?__gda__=exp=1587689482~hmac=42c0483b851c
######################################################################## 100.0%
==> Pouring coreutils-8.32.mojave.bottle.tar.gz
==> Caveats
Commands also provided by macOS have been installed with the prefix "g".
If you need to use these commands with their normal names, you
can add a "gnubin" directory to your PATH from your bashrc like:
  PATH="/usr/local/opt/coreutils/libexec/gnubin:$PATH"
==> Summary
🍺  /usr/local/Cellar/coreutils/8.32: 476 files, 8.8MB

Note the path to all the coreutils which can be added to your system $PATH

Remove tab bar from Firefox

As of FF 71.0 on macOS Mojave, edit the following file (creating it and its directory if they don't exist)...

Library/Application Support/Firefox/Profiles///chrome/userChrome.css

and add this snippet...

/* hides the native tabs
 */
#TabsToolbar {
  visibility: collapse;
}

Restart FF

Installing and Updating Node.js

Install node.js and manage versions with nvm

Add to .bash_profile...

#---
## Replaces current node with latest, keeping installed global packages
#---
function nvm-upgrade {
    CURR=$(nvm current)
    nvm install node --reinstall-packages-from=node
    nvm uninstall $CURR
}

Running vim in "vanilla" mode

vim -u x --noplugin     where x is an empty file

Docker CLI commands, most used by me

Docker command docker, used when managing individual containers on a docker engine. It is the client command line to access the docker daemon API

docker build - build an image from Dockerfile
docker container - manage one or more docker containers, takes a second argument (ps, rm, etc...)
docker exec - run a command in a running container
docker images - list all docker images
docker info - display a ton of system info for all docker containers
docker port - list port mappings, possibly for a single container
docker ps - list all docker containers
docker rm - remove one or more docker containers
docker rmi - remove one or more docker images
docker run - run d command in a new docker container

Docker command docker-compose, used to manage a multi-container application. It also moves many of the options you would enter on the docker run CLI into the docker-compose.yml file for easier reuse. It works as a front end "script" on top of the same docker API used by docker, so you can do everything docker-compose does with docker commands and a lot of shell scripting

docker-compose build - build or rebuild services
docker-compose exec - execute a command in a running container
docker-compose help - get help in
docker-compose images - list images
docker-compose ps - list containers
docker-compose up - build and start containers
docker-compose version - docker-compose version number

Docker command docker-machine, uses containerization to manage multiple images and containers and volumes and such: a container is basically a lightweight virtual machine

docker-machine create - create a new virtual machine
docker-machine env - display the commands to set up the environment for the Docker client
docker-machine kill - kill a machine
docker-machine ls - list all machines
docker-machine regenerate-certs - regenerate TLS certs for a machine
docker-machine restart - restart a machine
docker-machine rm - remove a machine
docker-machine ssh - log into or run a command on a machine with ssh
docker-machine start - start a machine
docker-machine version - show the docker machine version number

Removing an application manually from OS/X

After looking this up a million times, time to add it here...

• rm -rf /Applications/APPNAME
• rm -rf ~/Library/Preferences/APPFILES
• rm -rf ~/Library/Caches/APPFILES
• rm -rf ~/Library/Application\ Support/APPFILES
• rm -rf ~/Library/Logs/APPFILES