htop - Process Management¶
Every system administrator likes to use some of the more commonly used commands. Today I recommend
htop as an alternative to the
top command. To use the
htop command usually, you need to install it first.
# Installation epel source (also called repository)
dnf -y install epel-release
# Generate cache
# Install htop
dnf -y install htop
You only need to type
htop in the terminal, and the interactive interface is as follows:
0[ ||| 3%] Tasks: 22, 46thr, 174 kthr 1 running
1[ | 1%] Load average: 0.00 0.00 0.05
Mem[ ||||||| 197M/8G] Uptime: 00:31:39
PID USER PRI NI VIRT RES SHR S CPU% MEM% TIME+ Command(merged)
F1Help F2Setup F3Search F4Filter F5Tree F6SortBy F7Nice F8Nice+ F9Kill F10Quit
The top 0 and 1 indicate the number of your CPU cores, and the percentage indicates the occupancy rate of a single core (of course, the total occupancy rate of the CPU can also be displayed)
The different colors of the progress bar indicate the percentage of different process types:
Color Description Names displayed in other styles Blue Percentage of CPU used by low-priority processes low Green Percentage of process CPU owned by ordinary users Red Percentage of CPU used by system processes sys Cyan Percentage of CPU consumed by Steal Time vir
Tasks: 22, 46thr, 174 kthr 1 running. In my example, it means that my current machine has 22 tasks, which are divided into 46 threads, of which only 1 process is in a running state, "kthr" indicates how many kernel threads there are.
- Mem information. Similarly, use different colors to distinguish:
|Names displayed in other styles
|Percentage of memory consumed by the buffer
|Percentage of memory consumed by the memory area
|Percentage of memory consumed by the cache area
|Percentage of memory occupied by shared memory area
- Swap information.
|Names displayed in other styles
|Percentage of swap consumed by the swap area
|Percentage of swap consumed by the cache area
- Load average, the three values respectively represent the average load of the system in the last 1 minute, the last 5 minutes, and the last 15 minutes
- Uptime, which means the running time after booting
Process information description¶
- PID - Process ID number
- USER - The owner of the process
- PRI - Displays the process priority as seen by the Linux kernel
- NI - Displays the process priority of reset by normal user or root super user
- VIRT - Virtual memory being consumed by a process
- RES - Physical memory being consumed by a process
- SHR - Shared memory being consumed by a process
- S - The current state of the process, there is a special state to pay attention to! That is Z (zombie process). When there are a large number of zombie processes in the machine, it will affect the performance of the machine.
- CPU% - Percentage of CPU consumed by each process
- MEM% - Percentage of memory consumed by each process
- TIME+ - Shows the running time since the process was started
- Command - The command corresponding to the process
Shortcut key description¶
In the interactive interface, press the F1 button to see the corresponding shortcut key description.
- The up, down, left, and right direction keys can scroll through the interactive interface, and space can mark the corresponding process, which is marked in yellow.
- The N button, the P button, the M button and the T button are respectively PID, CPU%, MEM%, TIME+ is used for sorting. Of course, you can also use the mouse to click to sort in ascending or descending order of a certain field.
Other commonly used¶
To manage the process, use the F9 button to send different signals to the process. The list of signals can be found in
kill -l. The more commonly used ones are:
|Lets the process shut down immediately, and then restart after re-reading the configuration file
|Used to immediately end the running of the program, used to forcibly terminate the process, similar to the forced end in the windows taskbar
|The default signal for the kill command. Sometimes if a problem has occurred in the process and the process cannot be terminated normally with this signal, we will try signal 9
htop is much easier to use than the
top that comes with the system, it is more intuitive, and it improves daily use greatly. This is why
htop is usually one of the first packages the author installs after installing a new operating system.
Author: tianci li
Contributors: Steven Spencer