12 TOP Command Examples in Linux

This is the part of our on-going series of commands in Linux. We have covered basic ls command and cat command. In this article, we are trying to explore top command which is one of the most frequently used commands in our daily system administrative jobs. top command displays processor activity of your Linux box and also displays tasks managed by kernel in real-time. It’ll show processor and memory are being used and other information like running processes. This may help you to take correct action. top command found in UNIX-like operating systems.

Linux Top Command Examples

Linux Top Command Examples

You might also be interested in following tutorials :

  1. Htop (Linux Process Monitoring) tool for RHEL, CentOS & Fedora
  2. Iotop (Monitor Linux Disk I/O) in RHEL, CentOS and Fedora

1. Display of Top Command

In this example, it will show information like tasks, memory, cpu and swap. Press ‘q‘ to quit window.

# top
Linux Top Command

Linux Top Command

2. Sorting with -O (Uppercase Letter ‘O’).

Press (Shift+O) to Sort field via field letter, for example press ‘a‘ letter to sort process with PID (Process ID).

Sorting Process ID's with Top

Sorting Process ID’s with Top

Type any key to return to main top window with sorted PID order as shown in below screen. Press ‘q‘ to quit exit the window.

Sorting Process ID's

Sorting Process ID’s

3. Display Specific User Process

Use top command with ‘u‘ option will display specific User process details.

# top -u tecmint
Top with Specific User Processes

Top with Specific User Processes

4. Highlight Running Process in Top

Press ‘z‘ option in running top command will display running process in color which may help you to identified running process easily.

Top Process with Colorful

Top Process with Colorful

5. Shows Absolute Path of Processes

Press ‘c‘ option in running top command, it will display absolute path of running process.

Top with Specific Process Path

Top with Specific Process Path

6. Change Delay or Set ‘Screen Refresh Interval’ in Top

By default screen refresh interval is 3.0 seconds, same can be change pressing ‘d‘ option in running top command and change it as desired as shown below.

Top - Set Refresh Time

Top – Set Refresh Time

7. Kill running process with argument ‘k’

You can kill a process after finding PID of process by pressing ‘k‘ option in running top command without exiting from top window as shown below.

Top - Kill Process ID

Top – Kill Process ID

8. Sort by CPU Utilisation

Press (Shift+P) to sort processes as per CPU utilization. See screenshot below.

Top - High CPU Utilization

Top – High CPU Utilization

9. Renice a Process

You can use ‘r‘ option to change the priority of the process also called Renice.

Top - Renice Process

Top – Renice Process

10. Save Top Command Results

To save the running top command results output to a file /root/.toprc use the following command.

# top -n 1 -b > top-output.txt
Top Command Save Results

Top Command Save Results

11. Getting Top Command Help

Press ‘h‘ option to obtain the top command help.

Top Command Help

Top Command Help

12. Exit Top Command After Specific repetition

Top output keep refreshing until you press ‘q‘. With below command top command will automatically exit after 10 number of repetition.

# top -n 10

There are number of arguments to know more about top command you may refer man page of top command. Please share it if you find this article useful through our comment box below.

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80 Responses

  1. madhav says:

    Can you explain use of options in this command.

    # top -n 1 -b > top-output.txt
    
    • Ravi Saive says:

      @Madhav,

      The -n option specifies the maximum number of iterations and -b enables batch mode operation, which could be useful for sending output from top to a file.

  2. Khim says:

    Nice article, but how to search and see specific process memory and CPU utilization?

  3. Rupesh Kolatwar says:

    very nice Article…!!!

  4. Jai says:

    basically I want this output to a file.. for 10 mins..

    top – 13:29:09 up 1 day, 20:30, 1 user, load average: 0.65, 0.70, 0.69
    Tasks: 1022 total, 1 running, 1020 sleeping, 0 stopped, 1 zombie
    %Cpu0 : 13.0 us, 2.7 sy, 0.0 ni, 84.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
    %Cpu1 : 49.3 us, 3.6 sy, 0.0 ni, 45.7 id, 0.3 wa, 0.3 hi, 0.0 si, 0.7 st
    %Cpu2 : 2.0 us, 2.0 sy, 0.0 ni, 95.4 id, 0.0 wa, 0.3 hi, 0.3 si, 0.0 st
    %Cpu3 : 7.6 us, 2.0 sy, 0.0 ni, 90.4 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
    %Cpu4 : 1.3 us, 2.3 sy, 0.0 ni, 96.0 id, 0.0 wa, 0.0 hi, 0.3 si, 0.0 st
    %Cpu5 : 26.1 us, 2.6 sy, 0.0 ni, 70.3 id, 0.3 wa, 0.3 hi, 0.0 si, 0.3 st
    KiB Mem : 41042384 total, 1621820 free, 6024132 used, 33396432 buff/cache
    KiB Swap: 21946356 total, 21946308 free, 48 used. 9811332 avail Mem

    PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
    34389 root 20 0 967380 57812 8156 S 91.7 0.1 243:41.66 java
    4295 oracle 20 0 4517788 497680 9364 S 0.0 1.2 4:15.28 java

  5. Jai says:

    Hi All, is there a way to get top output for a given command only listing all CPU info also and write to a file..

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