Month: December 2019

bash git prompt

Git Status on Prompt

When you edit files in terminal, you can’t really tell how many files have been changed, staged and/or committed at a glance.

bash-git-prompt is an open source utility that helps you keep track on files under Git. Once you install it (the instruction is on their site), you can see the basic statistics in the prompt.

All up to date

File has been added but not staged yet

File has been staged

File has been committed but not pushed to the remote server

File has been changed but not staged

Recap

All the file status under Git can be accessed by executing the following command:

git status

It’s very convenient to be able to on the prompt without having to execute it.

Start Oracle VirtualBox VM with bash

I just came up with a way to start a Oracle VirtualBox VM with bash. Here is the code.

#!/bin/bash
vmname='Windows10'
cnt=$(VBoxManage showvminfo $vmname | grep -c 'running (since')
if [ $cnt -gt 0 ]; then
    logger "$vmname VM is already running"
else
    logger "Starting $vmname VM..."
    VBoxManage startvm $vmname --type headless
    logger "$vmname VM started successfully"
fi

The line #3 checks if it can find ‘running (since’ string in the standard output after running VBoxManage showvminfo $vmname and it assigns the occurrence count to cnt variable.

logger is the command you use to write log to /var/log/syslog. If the cnt value is greater than 0 (a positive number),  it writes out a message indicating that it’s already running in /var/log/syslog.

If it detects the VM is not running, it executes VBoxManage startvm $vmname –type headless to start the virtual machine.

This bash script could be run on startup or periodically in crontab or just be executed by hand.

Edit: If you add the following line to your crontab -e, it automatically starts the VM on startup.

@reboot /path/toyour/script/start-win10.sh

Enjoy!