Menu
On Unix-like operating systems, the tail command reads a file, and outputs the last part of it (the 'tail').
The tail command can also monitor data streams and open files, displaying new information as it is written. For example, it's a useful way to monitor the newest events in a system log in real time.
Nov 16, 2019 Tutorial on using tail, a UNIX and Linux command for outputting the last part of files. Examples of outputting the last ten lines of a file, limiting the number of lines, limiting the number of bytes, showing multiple files, watching a file for changes and using pipes.
This document covers the GNU/Linux version of tail.
Description
By default, tail prints the last 10 lines of each file to standard output. If you specify more than one file, each set of output is prefixed with a header showing the file name.
If no file is specified, or if file is a dash ('-'), tail reads from standard input.
SyntaxOptions
Examples
Outputs the last 10 lines of the file myfile.txt.
Outputs the last 100 lines of the file myfile.txt.
Outputs the last 10 lines of myfile.txt, and monitors myfile.txt for updates; tail then continues to output any new lines that are added to myfile.txt.
Tip: tail will follow the file forever. To stop it, press CTRL + C.
This is a useful example of using tail and grep to selectively monitor a log file in real time.
In this command, tail monitors the file access.log. It pipesaccess.log's final ten lines, and any new lines added, to the greputility. grep reads the output from tail, and outputs only those lines which contain the IP address24.10.160.10.
Related commands
cat — Output the contents of a file.
head — Display the first lines of a file. more — Display text one screen at a time. pg — Browse page by page through text files.
In 2015, we worked on a complete rewrite on our installationinstructions. This work was extended in 2017 with the design of a newdownload page. The archive of our design process as well as pendingissues can be found in the ?correspondingblueprint.
Our previous instructions forced people to jump through many differentdocumentation pages and often to figure out by themselves what to do next. Seethis ?flowchart of the installation process as of2014.
The objective was to make this a linear process, to be follow step-by-step, andthat would take the user from our homepage up to starting on a Tails USB stickwith a Persistent Storage. But this process has to be adapted to the baseoperating system of the user or their technical expertise.
We decided to optimize it for first time and less technical users, while stillbeing usable by expert users.
The following scenarios are proposed:
The installation assistant is also adapted to cover 5 manual upgradescenarios:
The assistant is divided into four sections:
The installation assistant is basically presenting very similar content in manydifferent scenarios with small variations (slightly different steps, slightlydifferent terminology, etc.).
To reuse as much content as possible and reduce the quantity of text andtranslations, our implementation relies heavily on two tricks. Both arequite hackish but were the only solution we found to avoid duplicatingmassive amount of content in ikiwiki.
Ikiwiki inlines
The inline directive ofikiwiki allows embedding a file into another file to avoid duplicating content.It is quite limited and brittle, especially when used together with the POplugin. See #6907.
Conditional CSS content
To adapt a piece of content reused using ikiwiki inlines to the contextwhere it appears we are using CSS classes. For example, to introduce theprogram used to install an intermediary Tails on Windows and Linux wewrote:
![]()
Elements with the
windows class being only displayed in the Windowsscenario and elements with thelinux class being only displayed in the Linux scenario.
The router is a sequence of multiple choices that determines whichinstallation scenario to follow. It is divided by operating systems:
Notes:
The overview is a single page summarizing graphically:
For example, the content of the overview for installing from Windows isstored in wiki/src/install/win/usb-overview.html which includes a common block ofHTML stored in wiki/src/install/inc/overview.html and uses the
windows CSSclass to adapt to the scenario.
The download of the ISO image comes as a dedicated page between theoverview and steps (except for
install-clone , mac-clone , upgrade-clone , and expert ). Itis also available as a standalone page.
The download is split as a dedicated page (while still labeled as 'Step1') to make it harder for people to skip the verification. It is stillpossible to skip the download or even the verification but the link todo so is labeled as a warning.
Depending on the installation scenario, the download page points to thedownload of the ISO image (on
dvd and vm ) or the USB image (on allother scenarios).
We propose two download techniques displayed in equal weight and combinedwith two verification techniques that have a level of verification at least asgood as HTTPS:
Tails Command Line Mac Download Gratis
a. Direct download combined with a browser extension, called Tails Verification. See the dedicated design document for a security analysis of this technique.
Tails - Download And Verify (for USB Sticks)
b. BitTorrent download. The Torrent file is downloaded through HTTPS from our website and BitTorrent clients automatically verifies the download once completed.
We advertise OpenPGP verification as an optional verification technique,possibly done on top of the other two techniques and ideally through theOpenPGP Web-of-Trust. We assume that this technique is only relevant forpeople who are already knowledgeable about OpenPGP. As a consequence:
Mac Command Line Install
The steps for a given scenario is a very long page with step-by-stepinstructions of the whole process.
Tails - Enabling A Wireless Device
Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2020
Categories |