From d4ef22d511d955dfbe7341b0de86b3b4ef11ba64 Mon Sep 17 00:00:00 2001 From: Ezio Date: Sat, 9 Dec 2017 15:53:54 +0800 Subject: [PATCH] =?UTF-8?q?20171209-14=20=E9=80=89=E9=A2=98?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../20170413 More Unknown Linux Commands.md | 131 ++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 sources/tech/20170413 More Unknown Linux Commands.md diff --git a/sources/tech/20170413 More Unknown Linux Commands.md b/sources/tech/20170413 More Unknown Linux Commands.md new file mode 100644 index 0000000000..f5507d3802 --- /dev/null +++ b/sources/tech/20170413 More Unknown Linux Commands.md @@ -0,0 +1,131 @@ +More Unknown Linux Commands +============================================================ + + +![unknown Linux commands](https://www.linux.com/sites/lcom/files/styles/rendered_file/public/outer-limits-of-linux.jpg?itok=5L5xfj2v "unknown Linux commands") +>Explore the outer limits of Linux with Carla Schroder in this roundup of little-known utilities.[Creative Commons Zero][2]Pixabay + +A roundup of the fun and little-known utilities `termsaver`, `pv`, and `calendar`. `termsaver` is an ASCII screensaver for the console, and `pv` measures data throughput and simulates typing. Debian's `calendar` comes with a batch of different calendars, and instructions for making your own. + +![Linux commands](https://www.linux.com/sites/lcom/files/styles/floated_images/public/linux-commands-fig-1.png?itok=HveXXLLK "Linux commands") + +Figure 1: Star Wars screensaver.[Used with permission][1] + +### Terminal Screensaver + +Why should graphical desktops have all the fun with fancy screensavers? Install `termsaver` to enjoy fancy ASCII screensavers like matrix, clock, starwars, and a couple of not-safe-for-work screens. More on the NSFW screens in a moment. + +`termsaver` is included in Debian/Ubuntu, and if you're using a boring distro that doesn't package fun things (like CentOS), you can download it from [termsaver.brunobraga.net][7] and follow the simple installation instructions. + +Run `termsaver -h` to see a list of screens: + +``` + randtxt displays word in random places on screen + starwars runs the asciimation Star Wars movie + urlfetcher displays url contents with typing animation + quotes4all displays recent quotes from quotes4all.net + rssfeed displays rss feed information + matrix displays a matrix movie alike screensaver + clock displays a digital clock on screen + rfc randomly displays RFC contents + jokes4all displays recent jokes from jokes4all.net (NSFW) + asciiartfarts displays ascii images from asciiartfarts.com (NSFW) + programmer displays source code in typing animation + sysmon displays a graphical system monitor +``` + +Then run your chosen screen with `termsaver [screen name]`, e.g. `termsaver matrix`, and stop it with Ctrl+c. Get information on individual screens by running `termsaver [screen name] -h`. Figure 1 is from the `starwars` screen, which runs our old favorite [Asciimation Wars][8]. + +The not-safe-for-work screens pull in online feeds. They're not my cup of tea, but the good news is `termsaver` is a gaggle of Python scripts, so they're easy to hack to connect to any RSS feed you desire. + +### pv + +The `pv` command is one of those funny little utilities that lends itself to creative uses. Its intended use is monitoring data copying progress, like when you run `rsync` or create a `tar`archive. When you run `pv` without options the defaults are: + +* -p progress. + +* -t timer, total elapsed time. + +* -e, ETA, time to completion. This is often inaccurate as `pv` cannot always know the size of the data you are moving. + +* -r, rate counter, or throughput. + +* -b, byte counter. + +This is what an `rsync` transfer looks like: + +``` +$ rsync -av /home/carla/ /media/carla/backup/ | pv +sending incremental file list +[...] +103GiB 0:02:48 [ 615MiB/s] [ <=> +``` + +Create a tar archive like this example: + +``` +$ tar -czf - /file/path| (pv > backup.tgz) + 885MiB 0:00:30 [28.6MiB/s] [ <=> +``` + +`pv` monitors processes. To see maximum activity monitor a Web browser process. It is amazing how much activity that generates: + +``` +$ pv -d 3095 + 58:/home/carla/.pki/nssdb/key4.db: 0 B 0:00:33 + [ 0 B/s] [<=> ] + 78:/home/carla/.config/chromium/Default/Visited Links: + 256KiB 0:00:33 [ 0 B/s] [<=> ] + ] + 85:/home/carla/.con...romium/Default/data_reduction_proxy_leveldb/LOG: + 298 B 0:00:33 [ 0 B/s] [<=> ] +``` + +Somewhere on the Internet I stumbled across a most entertaining way to use `pv` to echo back what I type: + +``` +$ echo "typing random stuff to pipe through pv" | pv -qL 8 +typing random stuff to pipe through pv +``` + +The normal `echo` command prints the whole line at once. Piping it through `pv` makes it appear as though it is being re-typed. I have no idea if this has any practical value, but I like it. The `-L`controls the speed of the playback, in bytes per second. + +`pv` is one of those funny little old commands that has acquired a giant batch of options over the years, including fancy formatting options, multiple output options, and transfer speed modifiers. `man pv` reveals all. + +### /usr/bin/calendar + +It's amazing what you can learn by browsing `/usr/bin` and other commands directories, and reading man pages. `/usr/bin/calendar` on Debian/Ubuntu is a modification of the BSD calendar, but it omits the moon and sun phases. It retains multiple calendars including `calendar.computer, calendar.discordian, calendar.music`, and `calendar.lotr`. On my system the man page lists different calendars than exist in `/usr/bin/calendar`. This example displays the Lord of the Rings calendar for the next 60 days: + +``` +$ calendar -f /usr/share/calendar/calendar.lotr -A 60 +Apr 17 An unexpected party +Apr 23 Crowning of King Ellesar +May 19 Arwen leaves Lorian to wed King Ellesar +Jun 11 Sauron attacks Osgilliath +``` + +The calendars are plain text files so you can easily create your own. The easy way is to copy the format of the existing calendar files. `man calendar` contains detailed instructions for creating your own calendar file. + +Once again we come to the end too quickly. Take some time to cruise your own filesystem to dig up interesting commands to play with. + + _Learn more about Linux through the free ["Introduction to Linux" ][5]course from The Linux Foundation and edX._ + +-------------------------------------------------------------------------------- + +via: https://www.linux.com/learn/intro-to-linux/2017/4/more-unknown-linux-commands + +作者：[ CARLA SCHRODER][a] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://www.linux.com/users/cschroder +[1]:https://www.linux.com/licenses/category/used-permission +[2]:https://www.linux.com/licenses/category/creative-commons-zero +[3]:https://www.linux.com/files/images/linux-commands-fig-1png +[4]:https://www.linux.com/files/images/outer-limits-linuxjpg +[5]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux +[6]:https://www.addtoany.com/share#url=https%3A%2F%2Fwww.linux.com%2Flearn%2Fintro-to-linux%2F2017%2F4%2Fmore-unknown-linux-commands&title=More%20Unknown%20Linux%20Commands +[7]:http://termsaver.brunobraga.net/ +[8]:http://www.asciimation.co.nz/