zsolt-torok / widgets-shell

Widgets.sh

Story

Your friend saw a Windows administrator using widgets like this, but he uses Linux and asked you to help him out by writing something similar for his terminal.

What are you going to learn?

• Practice writing shell scripts
• Use environment variables in practice
• Use basic control structures
• Learn which files in Linux hide information about the system

Tasks

1. The behaviour of widget.sh should be controlled with the WIDGET_CONTROL enviromental variable. The contents of WIDGET_CONTROL are separated by commas and can be one or more of the following in any order: mem, cpu, proc, user, disk.

   • If WIDGET_CONTROL is not set widget.sh displays memory and cpu stats
   • If WIDGET_CONTROL is set widget.sh displays stats about the given parameters, e.g. if WIDGET_CONTROL=mem,user then memory and user stats are displayed

2. Write a script (mem.sh) that displays information about memory usage and free memory.

   • The script displays the amount of free memory
   • The script displays the amount of total memory

3. Write a script (cpu.sh) that displays information about the CPU.

   • The script displays the CPU's model name
   • The script displays the number of CPU cores
   • The script displays the CPU's clock frequency (in MHz or GHz)

4. Write a script (proc.sh) that displays the number of running processes.

   • The script displays the number of running processes.

5. Write a script (disk.sh) that displays the avaible disks and the total amount of free space.

   • The script displays all available disks (block devices), e.g. /dev/sda, /dev/sdb, etc.
   • The script displays the amount of total disk space
   • The script displays the amount of free space
   • The script displays the percentage of used disk space

6. [OPTIONAL] You've found a way to extract some nifty information from a file hidden deep inside in the Linux file hierarchy. Feel free to add this new functionalty similarly to the other scripts, like mem.sh and its friends.

   • Be creative! :)

General requirements

None

Hints

• Remeber, in Linux everything is a file! :)
• You can pipe the output of commands to grep and/or cut to filter relevant information
• You can find various information about memory and cpu in /proc/meminfo and /proc/cpuinfo
• You can find the list of users in /etc/passwd and groups in /etc/group
• You can find information about disk usgint the lsblk command and df for disk usage
• Most of the command's output can be written without headers using arguments for easier parsing for scripts

Background materials

• Shell Scripting Tutorial
• Shell Variables
• Shell scripting and system variables