ppsmon: Simple service to track packet per second rate so it can be used in shell prompts

ppsmon is a very simple service that reads /sys/class/net/$interface/ to keep track of packet transmission rates. It stores the current rate to a file in the RAM backed filesystem where it can be easily accessed for display in a shell-prompt. This is nothing special and is quite simple- the "service" is about 15 lines of bash, an infinite loop that reads from /sys to get basic statistics

Prerequisites

• Linux (because of the use of the /sys filesystem)
• oh-my-zsh (if you want to use the canned ppsmon.zsh-theme file)
• bash (if you want to use the bash prompt file)
• zsh (if you want to use the vanilla zsh prompt file)
• The nobody and nogroup user and group
• A network interface named eth0

If you want to change the network interface or the nobody/nogroup user to some other value, you can edit the etc/systemd/system/ppsmon.service file with minimal effort before installing

Caveats

First, be aware that it is possible that this service could be abused to potentially write the packet rate integer to an arbitrary location on the filesystem, though it doesn't seem clear that this is the case- just fair warning. This is a theoretical concern that I haven't looked too deeply into as it is mitigated significantly by the fact that only an uncontrolled integer value can be written and it can only be written with the privileges of the nobody user

Installation

You can manually copy the files into place or you can use the provided Makefile to make things quicker and less clunky

Makefile

make ohmyzsh: This will install the oh-my-zsh theme into your home directory oh-my-zsh installation make bash: This will install the Bash prompt file into your home directory into ~/.pps.prompt make zsh: This will install the zsh prompt file into your home directory into ~/.zsh.prompt make system: This will install the daemon into /usr/bin and the systemd service file into /etc/systemd/system

If the service file is not present, any of the Makefile targets will install it for you with a confirmation prompt

Post-Installation

• For oh-my-zsh, you will need to set ZSH_THEME=ppsmon in your ~/.zshrc
• For bash, you will need to add source ~/.pps.bash to your ~/.bashrc or ~/.bash_profile
• For zsh, you will need to add source ~/.pps.zshrc to your ~/.zshrc

For bash and zsh, make sure that you source the file last in your settings or the prompt may get overwritten by other rc scripts

As a user service instead of a system service

It may make more sense to have this as a user service in many cases, rather than a system-wide service. This depends on your configuration

Copyright

• [email protected], BSD 3-Clause License
• See COPYING
• That's right, I just copyrighted 15 lines of bash script