What is top Linux command?
The top command in Linux is a powerful utility used to monitor system resources such as CPU usage, memory utilization, and running processes in real-time. It allows users to identify performance bottlenecks and troubleshoot system issues effectively.
top Syntax:
Section titled “top Syntax:”top [options]top Options:
Section titled “top Options:”| Option | Description |
|---|---|
| -h, —help | Display help message |
| -d, —delay | Specify refresh interval in seconds |
| -p, —pid | Monitor specific process ID |
| -U, —user | Display processes of a specific user |
| -u, —user | Monitor only processes of a specific user |
Parameters:
Section titled “Parameters:”None
top Command Usage Examples:
Section titled “top Command Usage Examples:”Displaying Top Processes
Section titled “Displaying Top Processes”topDisplays a dynamic view of the top processes running on the system.
Sorting by CPU Usage
Section titled “Sorting by CPU Usage”top -o %CPUStarts top with the processes sorted by the CPU utilization in descending order.
Displaying Specific Number of Processes
Section titled “Displaying Specific Number of Processes”top -n 5Runs top and limits the output to display only the top 5 processes.
Showing Processes for a Specific User
Section titled “Showing Processes for a Specific User”top -u usernameLaunches top and filters the processes to show only those owned by the specified username.
Highlighting Threads
Section titled “Highlighting Threads”top -HStarts top in a mode where individual threads are displayed separately for processes.
How to use top?:
Section titled “How to use top?:”How do I use top in Linux?
Section titled “How do I use top in Linux?”To use the top command in bash, execute the following command:
topWhat options can I use with top in Linux?
Section titled “What options can I use with top in Linux?”To specify options with the top command in Linux, you can use flags such as ‘-d’ to set the delay time between updates. For example:
top -d 5How can I sort processes in top by CPU usage?
Section titled “How can I sort processes in top by CPU usage?”To sort the processes displayed by top in Linux by CPU usage, you can press ‘Shift + P’ while within the top command. This will arrange the processes based on their CPU consumption.
How can I sort processes in top by memory usage?
Section titled “How can I sort processes in top by memory usage?”To sort the processes displayed by top in Linux by memory usage, you can press ‘Shift + M’ while within the top command. This will arrange the processes based on their memory consumption.
How to display a specific number of processes in top?
Section titled “How to display a specific number of processes in top?”To set the number of processes shown in the top command in Linux, you can use the ‘-n’ flag followed by the desired number. For example, to display only 10 processes, you can use:
top -n 10How to highlight running processes in top?
Section titled “How to highlight running processes in top?”To highlight running processes in the top command in Linux, you can press ‘z’ while within the top interface. This action will display running processes in a different color for easier identification.
How can I kill a process using top in Linux?
Section titled “How can I kill a process using top in Linux?”To kill a process using the top command in Linux, you can press ‘k’ while within the top interface. You will be prompted to enter the PID (Process ID) of the process you wish to terminate.
How can I save the current configuration in top for future use?
Section titled “How can I save the current configuration in top for future use?”To save the current configuration settings in the top command for future use, press ‘W’ while within the top interface. This will write the configuration to a file named ‘.toprc’ in your home directory.
Applications of the top command
Section titled “Applications of the top command”- Monitor system resource usage
- View running processes
- Check CPU and memory usage
- Sort processes by different metrics
- Kill processes
- Toggle between different display modes
- Analyze system performance