Operation and Maintenance
Linux Operation and Maintenance
What to do if the linux top command cannot be used
The Linux top command cannot be used because the top command is not installed in the system. The solution is to install the top command through the "apt-get install procps" or "yum install procps" command.
The operating environment of this tutorial: linux5.9.8 system, DELL G3 computer
What should I do if the linux top command cannot be used?
Solution:
top command displays or manages executing programs.
top command installation:
-bash: top: command not found #Debian apt-get install procps #Ubuntu apt-get install procps #Alpine apk add procps #Arch Linux pacman -S procps-ng #Kali Linux apt-get install procps #CentOS yum install procps #Fedora dnf install bro-devel #Raspbian apt-get install procps #Docker docker run cmd.cat/top top
top command supplementary description:
top command provides a dynamic real-time view of the running system. It can display system summary information, as well as a list of processes or threads currently being managed by the kernel. The type, order, and size of system summary information displayed, as well as the information displayed for tasks, are user-configurable.
The top command can dynamically view the overall operation of the system in real time. It is a practical tool that integrates multi-party information monitoring system performance and operation information. The interactive interface provided by the top command can be managed using hotkeys.
top command syntax:
top -hv | -bcHisS -d delay -n limit -u|U user | -p pid -w [cols]
top command options:
-b：以批處理模式操作； -c：顯示完整的治命令； -d：屏幕刷新間隔時間； -I：忽略失效過程； -s：保密模式； -S：累積模式； -i<時間>：設置間隔時間； -u<用戶名>：指定用戶名； -p<進程號>：指定進程； -n<次數(shù)>：循環(huán)顯示的次數(shù)。
top interactive commands:
Some interactive commands that can be used during the execution of the top command . These commands are single-letter, and some of them may be blocked if the -s option is used on the command line.
h：顯示幫助畫面，給出一些簡短的命令總結說明； k：終止一個進程； i：忽略閑置和僵死進程，這是一個開關式命令； q：退出程序； r：重新安排一個進程的優(yōu)先級別； S：切換到累計模式； s：改變兩次刷新之間的延遲時間（單位為s），如果有小數(shù)，就換算成ms。輸入0值則系統(tǒng)將不斷刷新，默認值是5s； f或者F：從當前顯示中添加或者刪除項目； o或者O：改變顯示項目的順序； l：切換顯示平均負載和啟動時間信息； m：切換顯示內存信息； t：切換顯示進程和CPU狀態(tài)信息； c：切換顯示命令名稱和完整命令行； M：根據駐留內存大小進行排序； P：根據CPU使用百分比大小進行排序； T：根據時間/累計時間進行排序； w：將當前設置寫入~/.toprc文件中。
top Command Example:
top Command The first thing I look at is the load average, which is in the upper right corner of the screen.
top - 12:08:45 up 33 days, 1:54, 1 user, load average: 0.08, 0.06, 0.07 Tasks: 135 total, 1 running, 134 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.1 us, 0.1 sy, 0.0 ni, 99.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 8008852 total, 230652 free, 1469292 used, 6308908 buff/cache KiB Swap: 0 total, 0 free, 0 used. 5702188 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1324 mysql 20 0 2636652 515728 8364 S 0.0 6.4 42:18.91 mysqld 3282 root 20 0 775876 127856 4448 S 0.0 1.6 62:03.92 jcloudhids 8572 nginx 20 0 80604 28032 2876 S 0.0 0.4 4:01.75 nginx 8571 nginx 20 0 80432 27916 2872 S 0.0 0.3 2:50.95 nginx 8570 nginx 20 0 80096 27636 2860 S 0.0 0.3 2:11.52 nginx 8574 nginx 20 0 80128 27592 2860 S 0.0 0.3 1:50.45 nginx 8569 nginx 20 0 80000 27360 2860 S 0.0 0.3 1:22.07 nginx 8567 nginx 20 0 79992 27340 2868 S 0.0 0.3 1:31.04 nginx 8568 nginx 20 0 79776 26988 2448 S 0.0 0.3 1:26.74 nginx 8573 nginx 20 0 79756 26984 2456 S 0.0 0.3 1:37.43 nginx 804 root 20 0 445200 24152 644 S 0.3 0.3 25:55.03 memcached 11255 nginx 20 0 340444 19900 5740 S 0.0 0.2 0:03.93 php-fpm 7525 nginx 20 0 340332 19744 5744 S 0.0 0.2 0:03.97 php-fpm
Pay attention to the area: "Cpu(s):" This line is in the middle of the header information. In particular, I'm interested in %us, sy%, %id, and %wa, which are user processes, system processes, idle time, and the proportion of time the CPU spends waiting for I/O streams to execute, respectively. This percentage should be close to 0, and anything above 5% needs to be watched closely.
top - 12:08:45[當前系統(tǒng)時間], 33 days[系統(tǒng)已經運行了33天], 1 user[個用戶當前登錄], load average: 0.08, 0.06, 0.07[系統(tǒng)負載，即任務隊列的平均長度] Tasks: 135 total[總進程數(shù)], 1 running[正在運行的進程數(shù)], 134 sleeping[睡眠的進程數(shù)], 0 stopped[停止的進程數(shù)], 0 zombie[凍結進程數(shù)], Cpu(s): 0.1%us[用戶空間占用CPU百分比], 0.1%sy[內核空間占用CPU百分比], 0.0%ni[用戶進程空間內改變過優(yōu)先級的進程占用CPU百分比], 0.2%id[空閑CPU百分比], 0.0%wa[等待輸入輸出的CPU時間百分比], 0.0%hi[], 0.0%st[], Mem: 8008852k total[物理內存總量], 1469292k used[使用的物理內存總量], 230652k free[空閑內存總量], 158188k buffers[用作內核緩存的內存量] Swap: 0k total[交換區(qū)總量], 0 used[使用的交換區(qū)總量], 0 free[空閑交換區(qū)總量], 0 cached[緩沖的交換區(qū)總量]
Recommended learning: "Linux Video Tutorial"
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