## 命令執行進度 ``` PV ("Pipe Viewer") is a tool for monitoring the progress of data through a pipeline. It can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion. ``` 顯示當前在命令行執行的命令的進度信息，管道查看器。 ## 補充說明 **pv命令**Pipe Viewer 的簡稱，由Andrew Wood 開發。意思是通過管道顯示數據處理進度的信息。這些信息包括已經耗費的時間，完成的百分比(通過進度條顯示)，當前的速度，全部傳輸的數據，以及估計剩余的時間。 ## 下載安裝 ~~~bash # Debian 系的操作系統，如 Ubuntu sudo apt-get install pv # RedHat系的則這樣： yum install pv ~~~ ### 語法 ~~~bash pv(選項)(參數) pv [OPTION] [FILE]... ~~~ ### 選項 ~~~ -p, --progress show progress bar -t, --timer show elapsed time -e, --eta show estimated time of arrival (completion) -I, --fineta show absolute estimated time of arrival (completion) -r, --rate show data transfer rate counter -a, --average-rate show data transfer average rate counter -b, --bytes show number of bytes transferred -T, --buffer-percent show percentage of transfer buffer in use -A, --last-written NUM show NUM bytes last written -F, --format FORMAT set output format to FORMAT -n, --numeric 輸出百分比 -q, --quiet do not output any transfer information at all -W, --wait display nothing until first byte transferred -D, --delay-start SEC display nothing until SEC seconds have passed -s, --size SIZE set estimated data size to SIZE bytes -l, --line-mode count lines instead of bytes -0, --null lines are null-terminated -i, --interval SEC update every SEC seconds -w, --width WIDTH assume terminal is WIDTH characters wide -H, --height HEIGHT assume terminal is HEIGHT rows high -N, --name NAME prefix visual information with NAME -f, --force output even if standard error is not a terminal -c, --cursor use cursor positioning escape sequences -L, --rate-limit RATE limit transfer to RATE bytes per second -B, --buffer-size BYTES use a buffer size of BYTES -C, --no-splice never use splice(), always use read/write -E, --skip-errors skip read errors in input -S, --stop-at-size stop after --size bytes have been transferred -R, --remote PID update settings of process PID -P, --pidfile FILE save process ID in FILE -d, --watchfd PID[:FD] watch file FD opened by process PID -h, --help 顯示幫助 -V, --version 顯示版本信息 ~~~ ### 實例 我們（在 linux 上使用命令行的用戶）的大多數使用場景都會用到的命令是從一個 USB 驅動器拷貝電影文件到你的電腦。如果你使用 cp 來完成上面的任務，你會什么情況都不清楚，直到整個復制過程結束或者出錯。 ~~~bash # 復制文件會有進度 # pv ~/Downloads/CentOS-7-x86_64-Minimal-1511.iso > ~/Desktop/CentOS-7-x86_64-Minimal-1511.iso # 下面輸入信息 552MiB 0:00:02 [ 212MiB/s] [==================> ] 91% ETA 0:00:00 # -L 可以讓你修改 pv 命令的傳輸速率。 # 使用 -L 選項來限制傳輸速率為2MB/s。 pv -L 2m /media/himanshu/1AC2-A8E3/fNf.mkv > ./Desktop/fnf.mkv ~~~ ~~~bash # 字符一個個勻速在命令行中顯示出來 echo "Tecmint[dot]com is a community of Linux Nerds and Geeks" | pv -qL 10 # 壓縮文件展示進度信息 pv /media/himanshu/1AC2-A8E3/fnf.mkv | gzip > ./Desktop/fnf.log.gz ~~~ ## 測試網速 ~~~ # 服務端 cat /dev/zero | pv | nc -l -p 2222 # 客戶端 nc localhost 2222 | pv ~~~