How to display CPU usage in tmux?

Detailed Explanation

Monitoring CPU usage directly in your tmux status bar can be helpful for system administrators, developers, and power users who need to keep an eye on system resources while working.

Method 1: Using the tmux-cpu Plugin

The easiest way to display CPU usage is with the tmux-cpu plugin:

# Step 1: Install TPM if you haven't already
git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm

# Step 2: Add the plugin to your ~/.tmux.conf
set -g @plugin 'tmux-plugins/tpm'
set -g @plugin 'tmux-plugins/tmux-cpu'

# Step 3: Add CPU information to your status line
set -g status-right "CPU: #{cpu_percentage} | %H:%M"

# Step 4: Initialize TMUX plugin manager (keep this at the bottom)
run '~/.tmux/plugins/tpm/tpm'

After adding these lines, reload your tmux configuration with Ctrl+b : source-file ~/.tmux.conf and install the plugin with Ctrl+b I.

Available Format Strings

The tmux-cpu plugin provides several format strings:

• #{cpu_percentage} - Shows CPU usage percentage
• #{cpu_icon} - Shows a CPU icon that changes color based on usage
• #{cpu_bg_color} - Changes background color based on CPU load
• #{ram_percentage} - Shows RAM usage percentage
• #{ram_icon} - Shows a RAM icon that changes color
• #{gpu_percentage} - Shows GPU usage percentage (if supported)

You can combine these in your status line configuration:

set -g status-right "#{cpu_icon} #{cpu_percentage} | #{ram_icon} #{ram_percentage} | %H:%M"

Method 2: Custom Script

If you prefer not to use a plugin, you can create a custom solution using shell commands and tmux's ability to run external commands in the status line:

# Create a script to get CPU usage (save as ~/bin/cpu_usage.sh)
#!/bin/bash

# Get CPU usage as a percentage
cpu_usage=$(top -bn1 | grep "Cpu(s)" | sed "s/.*, *\([0-9.]*\)%* id.*/\1/" | awk '{print 100 - $1"%"}')
echo "$cpu_usage"

# Make it executable
chmod +x ~/bin/cpu_usage.sh

# Then in your ~/.tmux.conf
set -g status-interval 5  # Update every 5 seconds
set -g status-right "#[fg=green]CPU: #(~/bin/cpu_usage.sh) | %H:%M"

This approach runs the script every 5 seconds to update the CPU usage in your status bar. You may need to adjust the CPU usage calculation based on your operating system.

Platform-Specific Scripts

# For macOS (save as ~/bin/cpu_usage_mac.sh)
#!/bin/bash
top -l 1 | grep -E "^CPU" | awk '{print $3+$5"%"}'

# For Linux (save as ~/bin/cpu_usage_linux.sh)
#!/bin/bash
grep 'cpu ' /proc/stat | awk '{usage=($2+$4)*100/($2+$4+$5)} END {print usage "%"}'

# Add to your ~/.tmux.conf
set -g status-right "\
#[fg=green,bg=default]#($HOME/bin/cpu_usage.sh < 30 && echo '#[fg=green]' || echo '#[fg=yellow]')\
#($HOME/bin/cpu_usage.sh > 70 && echo '#[fg=red]' || echo '')\
CPU: #($HOME/bin/cpu_usage.sh) #[fg=default]| %H:%M"

# Full system monitoring in status bar
set -g status-right "\
CPU: #{cpu_percentage} \
RAM: #{ram_percentage} \
| #[fg=cyan]#(df -h | grep '/$' | awk '{print $5}') \
| #[fg=green]↑#(uptime | awk '{print $3,$4}' | sed 's/,//') \
| #[fg=white]%a %d-%b %H:%M"