In Unix and Unix-like systems, tree is a recursive directory listing program that produces a depth-indented listing of files.
With no arguments, tree lists the files in the current directory. When directory arguments are given, tree lists all the files or directories found in the given directories each in turn. Upon completion of listing all files and directories found, tree returns the total number of files and directories listed.
The Single UNIX Specification (SUS) is the collective name of a family of standards for computeroperating systems, compliance with which is required to qualify for to use the "UNIX" trademark. The core specifications of the SUS are developed and maintained by the Austin Group, which is a joint working group of IEEE, ISO JTC 1 SC22 and The Open Group. If an operating system is submitted to The Open Group for certification, and passes conformance tests, then it is termed to be compliant with a UNIX standard such as UNIX98 or UNIX03.
Very few BSD and Linux-based operating systems are submitted for compliance with the Single UNIX Specification, although system developers generally aim for compliance with POSIX standards, which form the core of the Single UNIX Specification.
History
1980s: Motivation
The SUS emerged from a mid-1980s project to standardize operating systeminterfaces for software designed for variants of the Unix operating system. The need for standardization arose because enterprises using computers wanted to be able to develop programs that could be used on the computer systems of different manufacturers without reimplementing the programs. Unix was selected as the basis for a standard system interface partly because it was manufacturer-neutral.
The Year 2038 problem is an issue for computing and data storage situations in which time values are stored or calculated as a signed 32-bit integer, and this number is interpreted as the number of seconds since 00:00:00 UTC on 1 January 1970 ("the epoch"). Such implementations cannot encode times after 03:14:07 UTC on 19 January 2038 (21 years' time), a problem similar to but not entirely analogous to the "Y2K problem" (also known as the "Millennium Bug"), in which 2-digit values representing the number of years since 1900 could not encode the year 2000 or later. Most 32-bitUnix-like systems store and manipulate time in this "Unix time" format, so the year 2038 problem is sometimes referred to as the "Unix Millennium Bug" by association.
Technical cause
The latest time that can be represented in Unix's signed 32-bit integer time format is 03:14:07 UTC on Tuesday, 19 January 2038 (2,147,483,647 seconds after 1 January 1970).
Times beyond that will "wrap around" and be stored internally as a negative number, which these systems will interpret as having occurred on 13 December 1901 rather than 19 January 2038. This is caused by integer overflow. The counter "runs out" of usable bits, "increments" the sign bit instead, and reports a maximally negative number (continuing to count up, toward zero). Resulting erroneous calculations on such systems are likely to cause problems for users and other relying parties.
In botany, a tree is a perennialplant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. In looser senses, the taller palms, the tree ferns, bananas and bamboos are also trees. Trees tend to be long-lived, some reaching several thousand years old. The tallest known tree, a coast redwood named Hyperion, stands 115.6m (379ft) high. Trees have been in existence for 370 million years. It is estimated that there are just over 3 trillion mature trees in the world.
A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark which serves as a protective barrier. Below the ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the branches divide into smaller branches and shoots. The shoots typically bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development. Flowers and fruit may also be present, but some trees, such as conifers, instead have pollen cones and seed cones; others, such as tree ferns, produce spores instead.
Trees are significant in many of the world's mythologies and religions, and have been given deep and sacred meanings throughout the ages. Human beings, observing the growth and death of trees, and the annual death and revival of their foliage, have often seen them as powerful symbols of growth, death and rebirth. Evergreen trees, which largely stay green throughout these cycles, are sometimes considered symbols of the eternal, immortality or fertility. The image of the Tree of life or world tree occurs in many mythologies.
The Wu Xing are chiefly an ancient mnemonic device for systems with 5 stages; hence the preferred translation of "tree" over "wood".
Attributes
In Chinese Taoist thought, Wood attributes are considered to be strength and flexibility, as with bamboo. It is also associated with qualities of warmth, generosity, co-operation and idealism. The Wood person will be expansive, outgoing and socially conscious. The wood element is one that seeks ways to grow and expand. Wood heralds the beginning of life, springtime and buds, sensuality and fecundity. Wood needs moisture to thrive.
What's the difference between Linux and Unix? They look and work the same but they don't seem to fundamentally be the same thing. Today, we take a closer look at what these differences are and how they've come about.
= 0612 TV =
0612 TV, a sub-project of NERDfirst.net, is an educational YouTube channel. Started in 2008, we have now covered a wide range of topics, from areas such as Programming, Algorithms and Computing Theories, Computer Graphics, Photography, and Specialized Guides for using software such as FFMPEG, Deshaker, GIMP and more!
Enjoy your stay, and don't hesitate to drop me a comment or a personal message to my inbox =) If you like my work, don't forget to subscribe!
Like what you see? Buy me a coffee → http://www.nerdfirst.net/donate/
0612 TV Official Writeup: http://ner...
published: 07 Mar 2018
Difference between POSIX, Single UNIX Specification, and Open Group Base Specifications?
Unix & Linux: Difference between POSIX, Single UNIX Specification, and Open Group Base Specifications?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Tim (https://unix.stackexchange.com/users/674), user R.. GitHub STOP HELPING ICE (https://unix.stackexchange.com/users/6342), user penguin359 (https://unix.stackexchange.com/users/6167), user Michael Mrozek (https://unix.stackexchange.com/users/73), user Daniel Beck (https://unix.stackexchange.com/users/5891), and the Stack Excha...
published: 14 Oct 2020
UNIX Unit1-The Unix Architecture, POSIX and Single UNIX Specification by Ashwini G T
BCA 6th Semester
published: 10 Jun 2021
Unix & Linux: Is Posix a subset of Single UNIX Specification? (2 Solutions!!)
Unix & Linux: Is Posix a subset of Single UNIX Specification?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Stephen Kitt (https://unix.stackexchange.com/users/86440), user schily (https://unix.stackexchange.com/users/120884), user Gilles 'SO- stop being evil' (https://unix.stackexchange.com/users/885), user Gabriele Scarlatti (https://unix.stackexchange.com/users/215663), and the Stack Exchange Network (http://unix.stackexchange.com/questions/419307). Trademarks are property ...
published: 19 Oct 2020
Unix-like
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification.
There is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system is "Unix-like".
This video is targeted to blind users.
Attribution:
Article text available under CC-BY-SA
Creative Commons image source in video
published: 27 Aug 2014
Advanced Programming in the UNIX Environment: Week 01 - Unix Basics
In this video lecture, we provide a whirlwind tour of the Unix programming environment. In the process, we write a simple shell, a simple version of the ls(1) command, and two versions of the cat(1) command.
Slides for this lecture: https://stevens.netmeister.org/631/01-basics.pdf
Course website: https://stevens.netmeister.org/631/
Related links:
https://www.netmeister.org/book/02-unix.pdf
Outline:
00:00 Introduction / OS Design
01:51 System Calls and Library Functions, Standards
11:02 Let's write some code already!
19:01 What exactly is a shell?
23:58 Program Design
26:45 Unix Pipes
28:05 Files and Directories
31:16 User IDs
32:09 Time Values
36:40 File Descriptors & Standard I/O
43:30 Processes
46:00 Signals
published: 29 Aug 2020
35 What does "unix like" mean?
published: 25 Dec 2020
UNIX Architecture and POSIX
UNIX Architecture and POSIX
published: 05 Dec 2020
Introduction To Unix and Unix-like operating systems
This video serves as a basic historical introduction to UNIX and UNIX-like operating systems.
What's the difference between Linux and Unix? They look and work the same but they don't seem to fundamentally be the same thing. Today, we take a closer look a...
What's the difference between Linux and Unix? They look and work the same but they don't seem to fundamentally be the same thing. Today, we take a closer look at what these differences are and how they've come about.
= 0612 TV =
0612 TV, a sub-project of NERDfirst.net, is an educational YouTube channel. Started in 2008, we have now covered a wide range of topics, from areas such as Programming, Algorithms and Computing Theories, Computer Graphics, Photography, and Specialized Guides for using software such as FFMPEG, Deshaker, GIMP and more!
Enjoy your stay, and don't hesitate to drop me a comment or a personal message to my inbox =) If you like my work, don't forget to subscribe!
Like what you see? Buy me a coffee → http://www.nerdfirst.net/donate/
0612 TV Official Writeup: http://nerdfirst.net/0612tv
More about me: http://about.me/lcc0612
Official Twitter: http://twitter.com/0612tv
= NERDfirst =
NERDfirst is a project allowing me to go above and beyond YouTube videos into areas like app and game development. It will also contain the official 0612 TV blog and other resources.
Watch this space, and keep your eyes peeled on this channel for more updates! http://nerdfirst.net/
-----
Disclaimer: Please note that any information is provided on this channel in good faith, but I cannot guarantee 100% accuracy / correctness on all content. Contributors to this channel are not to be held responsible for any possible outcomes from your use of the information.
What's the difference between Linux and Unix? They look and work the same but they don't seem to fundamentally be the same thing. Today, we take a closer look at what these differences are and how they've come about.
= 0612 TV =
0612 TV, a sub-project of NERDfirst.net, is an educational YouTube channel. Started in 2008, we have now covered a wide range of topics, from areas such as Programming, Algorithms and Computing Theories, Computer Graphics, Photography, and Specialized Guides for using software such as FFMPEG, Deshaker, GIMP and more!
Enjoy your stay, and don't hesitate to drop me a comment or a personal message to my inbox =) If you like my work, don't forget to subscribe!
Like what you see? Buy me a coffee → http://www.nerdfirst.net/donate/
0612 TV Official Writeup: http://nerdfirst.net/0612tv
More about me: http://about.me/lcc0612
Official Twitter: http://twitter.com/0612tv
= NERDfirst =
NERDfirst is a project allowing me to go above and beyond YouTube videos into areas like app and game development. It will also contain the official 0612 TV blog and other resources.
Watch this space, and keep your eyes peeled on this channel for more updates! http://nerdfirst.net/
-----
Disclaimer: Please note that any information is provided on this channel in good faith, but I cannot guarantee 100% accuracy / correctness on all content. Contributors to this channel are not to be held responsible for any possible outcomes from your use of the information.
Unix & Linux: Difference between POSIX, Single UNIX Specification, and Open Group Base Specifications?
Helpful? Please support me on Patreon: https://www.patr...
Unix & Linux: Difference between POSIX, Single UNIX Specification, and Open Group Base Specifications?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Tim (https://unix.stackexchange.com/users/674), user R.. GitHub STOP HELPING ICE (https://unix.stackexchange.com/users/6342), user penguin359 (https://unix.stackexchange.com/users/6167), user Michael Mrozek (https://unix.stackexchange.com/users/73), user Daniel Beck (https://unix.stackexchange.com/users/5891), and the Stack Exchange Network (http://unix.stackexchange.com/questions/14368). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.
Unix & Linux: Difference between POSIX, Single UNIX Specification, and Open Group Base Specifications?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Tim (https://unix.stackexchange.com/users/674), user R.. GitHub STOP HELPING ICE (https://unix.stackexchange.com/users/6342), user penguin359 (https://unix.stackexchange.com/users/6167), user Michael Mrozek (https://unix.stackexchange.com/users/73), user Daniel Beck (https://unix.stackexchange.com/users/5891), and the Stack Exchange Network (http://unix.stackexchange.com/questions/14368). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.
Unix & Linux: Is Posix a subset of Single UNIX Specification?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & prai...
Unix & Linux: Is Posix a subset of Single UNIX Specification?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Stephen Kitt (https://unix.stackexchange.com/users/86440), user schily (https://unix.stackexchange.com/users/120884), user Gilles 'SO- stop being evil' (https://unix.stackexchange.com/users/885), user Gabriele Scarlatti (https://unix.stackexchange.com/users/215663), and the Stack Exchange Network (http://unix.stackexchange.com/questions/419307). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.
Unix & Linux: Is Posix a subset of Single UNIX Specification?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Stephen Kitt (https://unix.stackexchange.com/users/86440), user schily (https://unix.stackexchange.com/users/120884), user Gilles 'SO- stop being evil' (https://unix.stackexchange.com/users/885), user Gabriele Scarlatti (https://unix.stackexchange.com/users/215663), and the Stack Exchange Network (http://unix.stackexchange.com/questions/419307). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming ...
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification.
There is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system is "Unix-like".
This video is targeted to blind users.
Attribution:
Article text available under CC-BY-SA
Creative Commons image source in video
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification.
There is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system is "Unix-like".
This video is targeted to blind users.
Attribution:
Article text available under CC-BY-SA
Creative Commons image source in video
In this video lecture, we provide a whirlwind tour of the Unix programming environment. In the process, we write a simple shell, a simple version of the ls(1) ...
In this video lecture, we provide a whirlwind tour of the Unix programming environment. In the process, we write a simple shell, a simple version of the ls(1) command, and two versions of the cat(1) command.
Slides for this lecture: https://stevens.netmeister.org/631/01-basics.pdf
Course website: https://stevens.netmeister.org/631/
Related links:
https://www.netmeister.org/book/02-unix.pdf
Outline:
00:00 Introduction / OS Design
01:51 System Calls and Library Functions, Standards
11:02 Let's write some code already!
19:01 What exactly is a shell?
23:58 Program Design
26:45 Unix Pipes
28:05 Files and Directories
31:16 User IDs
32:09 Time Values
36:40 File Descriptors & Standard I/O
43:30 Processes
46:00 Signals
In this video lecture, we provide a whirlwind tour of the Unix programming environment. In the process, we write a simple shell, a simple version of the ls(1) command, and two versions of the cat(1) command.
Slides for this lecture: https://stevens.netmeister.org/631/01-basics.pdf
Course website: https://stevens.netmeister.org/631/
Related links:
https://www.netmeister.org/book/02-unix.pdf
Outline:
00:00 Introduction / OS Design
01:51 System Calls and Library Functions, Standards
11:02 Let's write some code already!
19:01 What exactly is a shell?
23:58 Program Design
26:45 Unix Pipes
28:05 Files and Directories
31:16 User IDs
32:09 Time Values
36:40 File Descriptors & Standard I/O
43:30 Processes
46:00 Signals
What's the difference between Linux and Unix? They look and work the same but they don't seem to fundamentally be the same thing. Today, we take a closer look at what these differences are and how they've come about.
= 0612 TV =
0612 TV, a sub-project of NERDfirst.net, is an educational YouTube channel. Started in 2008, we have now covered a wide range of topics, from areas such as Programming, Algorithms and Computing Theories, Computer Graphics, Photography, and Specialized Guides for using software such as FFMPEG, Deshaker, GIMP and more!
Enjoy your stay, and don't hesitate to drop me a comment or a personal message to my inbox =) If you like my work, don't forget to subscribe!
Like what you see? Buy me a coffee → http://www.nerdfirst.net/donate/
0612 TV Official Writeup: http://nerdfirst.net/0612tv
More about me: http://about.me/lcc0612
Official Twitter: http://twitter.com/0612tv
= NERDfirst =
NERDfirst is a project allowing me to go above and beyond YouTube videos into areas like app and game development. It will also contain the official 0612 TV blog and other resources.
Watch this space, and keep your eyes peeled on this channel for more updates! http://nerdfirst.net/
-----
Disclaimer: Please note that any information is provided on this channel in good faith, but I cannot guarantee 100% accuracy / correctness on all content. Contributors to this channel are not to be held responsible for any possible outcomes from your use of the information.
Unix & Linux: Difference between POSIX, Single UNIX Specification, and Open Group Base Specifications?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Tim (https://unix.stackexchange.com/users/674), user R.. GitHub STOP HELPING ICE (https://unix.stackexchange.com/users/6342), user penguin359 (https://unix.stackexchange.com/users/6167), user Michael Mrozek (https://unix.stackexchange.com/users/73), user Daniel Beck (https://unix.stackexchange.com/users/5891), and the Stack Exchange Network (http://unix.stackexchange.com/questions/14368). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.
Unix & Linux: Is Posix a subset of Single UNIX Specification?
Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaar
With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Stephen Kitt (https://unix.stackexchange.com/users/86440), user schily (https://unix.stackexchange.com/users/120884), user Gilles 'SO- stop being evil' (https://unix.stackexchange.com/users/885), user Gabriele Scarlatti (https://unix.stackexchange.com/users/215663), and the Stack Exchange Network (http://unix.stackexchange.com/questions/419307). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification.
There is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system is "Unix-like".
This video is targeted to blind users.
Attribution:
Article text available under CC-BY-SA
Creative Commons image source in video
In this video lecture, we provide a whirlwind tour of the Unix programming environment. In the process, we write a simple shell, a simple version of the ls(1) command, and two versions of the cat(1) command.
Slides for this lecture: https://stevens.netmeister.org/631/01-basics.pdf
Course website: https://stevens.netmeister.org/631/
Related links:
https://www.netmeister.org/book/02-unix.pdf
Outline:
00:00 Introduction / OS Design
01:51 System Calls and Library Functions, Standards
11:02 Let's write some code already!
19:01 What exactly is a shell?
23:58 Program Design
26:45 Unix Pipes
28:05 Files and Directories
31:16 User IDs
32:09 Time Values
36:40 File Descriptors & Standard I/O
43:30 Processes
46:00 Signals
In Unix and Unix-like systems, tree is a recursive directory listing program that produces a depth-indented listing of files.
With no arguments, tree lists the files in the current directory. When directory arguments are given, tree lists all the files or directories found in the given directories each in turn. Upon completion of listing all files and directories found, tree returns the total number of files and directories listed.
But by a strange confluence of historical, technical, and legal reasons, Linux — and not a more central branch of the Unix family tree — took root and thrived like an invasive species ... Many Relatives, One FamilyTree.
Specifically, what I regard as key Unix principles I’ve found notably missing ... In Unix, everything is a file, and every file is somewhere in the file tree (starting at /).