It's that time of year again!
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It's that time of year again! The Fall semester is about to start, and I'm teaching "Advanced Programming in the UNIX Environment". The syllabus and all course materials including all code examples is available here:
https://stevens.netmeister.org/631/
All video lectures are public and available for free on YouTube:
https://www.youtube.com/@cs631apue/videos
If you want to follow along, I'll be posting lecture videos and related links in this thread throughout the semester.
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It's that time of year again! The Fall semester is about to start, and I'm teaching "Advanced Programming in the UNIX Environment". The syllabus and all course materials including all code examples is available here:
https://stevens.netmeister.org/631/
All video lectures are public and available for free on YouTube:
https://www.youtube.com/@cs631apue/videos
If you want to follow along, I'll be posting lecture videos and related links in this thread throughout the semester.
Advanced Programming the UNIX Environment
Week 1: Introduction
This video covers a lot of the meta information (what do we do, why are we doing it, how are we doing it, syllabus, etc.). Some things have changed since I created the video (for example, we now have an AI policy: https://stevens.netmeister.org/631/use-of-ai.html), but most of it remains accurate.
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Advanced Programming the UNIX Environment
Week 1: Introduction
This video covers a lot of the meta information (what do we do, why are we doing it, how are we doing it, syllabus, etc.). Some things have changed since I created the video (for example, we now have an AI policy: https://stevens.netmeister.org/631/use-of-ai.html), but most of it remains accurate.
Advanced Programming the UNIX Environment
Week 1: UNIX History
We cover the early days at Bell Labs, USL vs BSDi, the birth of the BSDs and Linux, and how we got from Ken Thompson playing "Space Travel" on a PDP-7 to Unix running on your phone, fridge, and TV.
Scroll along through it all here: https://www.levenez.com/unix/unix.pdf
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Advanced Programming the UNIX Environment
Week 1: UNIX History
We cover the early days at Bell Labs, USL vs BSDi, the birth of the BSDs and Linux, and how we got from Ken Thompson playing "Space Travel" on a PDP-7 to Unix running on your phone, fridge, and TV.
Scroll along through it all here: https://www.levenez.com/unix/unix.pdf
Advanced Programming the UNIX Environment
Week 1: UNIX Basics
In this 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 while learning about the Unix Philosophy.
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Advanced Programming the UNIX Environment
Week 1: UNIX Basics
In this 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 while learning about the Unix Philosophy.
Advanced Programming the UNIX Environment
Our reference platform for this class is NetBSD. Some ways to get set up are:
Use an AWS image:
https://stevens.netmeister.org/615/netbsd-amis.htmlCreate your own AWS image:
https://www.netmeister.org/blog/creating-netbsd-ec2-amis.html
https://www.netmeister.org/blog/netbsd-amd64-ami.htmlInstall NetBSD on a Linode:
https://www.netmeister.org/blog/netbsd-on-linode.htmlUse UTM / qemu:
https://stevens.netmeister.org/631/utm/ -
Advanced Programming the UNIX Environment
Our reference platform for this class is NetBSD. Some ways to get set up are:
Use an AWS image:
https://stevens.netmeister.org/615/netbsd-amis.htmlCreate your own AWS image:
https://www.netmeister.org/blog/creating-netbsd-ec2-amis.html
https://www.netmeister.org/blog/netbsd-amd64-ami.htmlInstall NetBSD on a Linode:
https://www.netmeister.org/blog/netbsd-on-linode.htmlUse UTM / qemu:
https://stevens.netmeister.org/631/utm/Advanced Programming the UNIX Environment
Some additional hints to set up your NetBSD environment for this class:
https://stevens.netmeister.org/631/vm-setup.html
With all sources extracted, familiarize yourself with ctags(1) et al to make browsing code a breeze:
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Advanced Programming the UNIX Environment
Some additional hints to set up your NetBSD environment for this class:
https://stevens.netmeister.org/631/vm-setup.html
With all sources extracted, familiarize yourself with ctags(1) et al to make browsing code a breeze:
Advanced Programming the UNIX Environment
Week 2: File Descriptors
To introduce the concept of file descriptors, let's start with a simple question: how many file descriptors can a unix process open? In the process we encounter different limits that may apply across the system, for a given user, or just a process.
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Advanced Programming the UNIX Environment
Week 2: File Descriptors
To introduce the concept of file descriptors, let's start with a simple question: how many file descriptors can a unix process open? In the process we encounter different limits that may apply across the system, for a given user, or just a process.
Advanced Programming in the UNIX Environment
Week 2: open(2) and close(2)
Having introduced the concept of file descriptors, let's look at what happens when we try to create a file, "create" an existing file, open an existing file, truncate a file, and look at the various other flags we can pass to open(2).
We also note the perhaps surprising number of ways in which open(2) can fail and take a look at openat(2) and TOCTOU defenses.
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Advanced Programming in the UNIX Environment
Week 2: open(2) and close(2)
Having introduced the concept of file descriptors, let's look at what happens when we try to create a file, "create" an existing file, open an existing file, truncate a file, and look at the various other flags we can pass to open(2).
We also note the perhaps surprising number of ways in which open(2) can fail and take a look at openat(2) and TOCTOU defenses.
Advanced Programming in the UNIX Environment
Week 2: read(2)/write(2)/lseek(2)
In this video lecture, we will go into the details of the read(2), write(2), and lseek(2). We'll also do a few weird things with file descriptors, and take a look at how we can ensure I/O efficiency when making these system calls.
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Advanced Programming in the UNIX Environment
Week 2: read(2)/write(2)/lseek(2)
In this video lecture, we will go into the details of the read(2), write(2), and lseek(2). We'll also do a few weird things with file descriptors, and take a look at how we can ensure I/O efficiency when making these system calls.
Advanced Programming in the UNIX Environment
Week 2: File Sharing
In this final video lecture segment for our week 2 materials, we take a look at what it means when multiple processes access the same files and what the implications of that are on the syscalls we know. We conclude with a look at /dev/fd on different operating systems, including #NetBSD, #macOS, and #Linux
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Advanced Programming in the UNIX Environment
Week 2: File Sharing
In this final video lecture segment for our week 2 materials, we take a look at what it means when multiple processes access the same files and what the implications of that are on the syscalls we know. We conclude with a look at /dev/fd on different operating systems, including #NetBSD, #macOS, and #Linux
Advanced Programming in the UNIX Environment
A we're starting to regularly write C code now, it might be good to share a few useful links:
How to C (as of 2016)
https://matt.sh/howto-cA critique of "How to C" by Matt:
https://github.com/Keith-S-Thompson/how-to-c-response/blob/master/README.mdand, even though you kids don't have any idea what Usenet is (now get off my lawn), the comp.lang.c FAQ:
https://c-faq.com/ -
Advanced Programming in the UNIX Environment
A we're starting to regularly write C code now, it might be good to share a few useful links:
How to C (as of 2016)
https://matt.sh/howto-cA critique of "How to C" by Matt:
https://github.com/Keith-S-Thompson/how-to-c-response/blob/master/README.mdand, even though you kids don't have any idea what Usenet is (now get off my lawn), the comp.lang.c FAQ:
https://c-faq.com/Advanced Programming in the UNIX Environment
Week 3: stat(2) intro
In this video lecture, we meet our new best friend, the 'struct stat'. We'll cover the stat(2) system calls and begin discussing each of the fields in the struct, often by example of the ls(1) and stat(1) commands. In this way, we begin learning more about how the Unix File System is implemented.
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Advanced Programming in the UNIX Environment
Week 3: stat(2) intro
In this video lecture, we meet our new best friend, the 'struct stat'. We'll cover the stat(2) system calls and begin discussing each of the fields in the struct, often by example of the ls(1) and stat(1) commands. In this way, we begin learning more about how the Unix File System is implemented.
Advanced Programming in the UNIX Environment
Week 3: UIDs intro
In this video lecture, we'll learn a little bit more about file ownership and the user IDs of a process (real, effective, saved) by looking at the seteuid(2) and setuid(2) system calls and experimenting with setting the setuid bits and observe the file access we gain.
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Advanced Programming in the UNIX Environment
Week 3: UIDs intro
In this video lecture, we'll learn a little bit more about file ownership and the user IDs of a process (real, effective, saved) by looking at the seteuid(2) and setuid(2) system calls and experimenting with setting the setuid bits and observe the file access we gain.
Advanced Programming in the UNIX Environment
Week 3: struct stat st_mode
In this video segment, we're looking at how the permissions defined in the `struct stat st_mode` are applied. You want to pay particular attention to the permissions on directories and the order in which they are checked.
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Advanced Programming in the UNIX Environment
Week 3: struct stat st_mode
In this video segment, we're looking at how the permissions defined in the `struct stat st_mode` are applied. You want to pay particular attention to the permissions on directories and the order in which they are checked.
Advanced Programming in the UNIX Environment
Week 3: chmod(2) and chown(2)
Having seen a lot of examples in our previous videos of creating files, changing their ownership, changing their permissions, we now focus on the system calls that are used to implement the chmod(1) and chown(8) commands.
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Advanced Programming in the UNIX Environment
Week 3: chmod(2) and chown(2)
Having seen a lot of examples in our previous videos of creating files, changing their ownership, changing their permissions, we now focus on the system calls that are used to implement the chmod(1) and chown(8) commands.
Advanced Programming in the UNIX Environment
Week 3: umask(2)
In this video lecture, we'll take a look at what file ownership and permissions are applied when we create a new file. In the process, we'll learn about the concept of a process's "umask", and look at how the 'umask' shell built-in is implemented.
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Advanced Programming in the UNIX Environment
Week 3: umask(2)
In this video lecture, we'll take a look at what file ownership and permissions are applied when we create a new file. In the process, we'll learn about the concept of a process's "umask", and look at how the 'umask' shell built-in is implemented.
Advanced Programming in the UNIX Environment
An illustration of how permission octal modes and umasks work.
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Advanced Programming in the UNIX Environment
An illustration of how permission octal modes and umasks work.
Advanced Programming in the UNIX Environment
Week 3: Union Mounts and Whiteout Files
One of the file types we've encountered are those of type S_IFWHT, so called "whiteout" files. But what the hell is that?? Let's illustrate! We describe the concept of union mounts and see what happens when a file in the upper layer is removed while the same file still exists in the lower layer: a whiteout file is created to cover up the lower file.
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Advanced Programming in the UNIX Environment
Week 3: Union Mounts and Whiteout Files
One of the file types we've encountered are those of type S_IFWHT, so called "whiteout" files. But what the hell is that?? Let's illustrate! We describe the concept of union mounts and see what happens when a file in the upper layer is removed while the same file still exists in the lower layer: a whiteout file is created to cover up the lower file.
Advanced Programming in the UNIX Environment
Week 4: The Unix Filesystem
In this video lecture, we begin a closer look at the Unix Filesystem (UFS). We visualize how the filesystem structures the disk and organizes files and directories. We illustrate how directory entries are created and moved around.
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Advanced Programming in the UNIX Environment
Week 4: The Unix Filesystem
In this video lecture, we begin a closer look at the Unix Filesystem (UFS). We visualize how the filesystem structures the disk and organizes files and directories. We illustrate how directory entries are created and moved around.
Advanced Programming in the UNIX Environment
Week 4: Links
In this video lecture, we'll take a look at the system calls used to create, remove, and rename both hard- and symbolic links. We'll compare expected output against trivial implementations of the ln(1) and mv(1) commands.
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Gli ultimi otto messaggi ricevuti dalla Federazione
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Il SI’ all’attacco della Costituzione
@giornalismo
articolo21.org/2026/03/il-si-a…
Ultimi dieci giorni di campagna referendaria. Non è difficile prevedere quanta violenza, aggressività, volgarità, falsità il governo Meloni e i suoi tanti lacché, presenti anche nel mondo dell’informazione, scateneranno contro il NO a quell’inganno che
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Thanks for the nice wishes!
Today, we mostly explored Franconia. 🥨 🇩🇪
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@Uilebheist @Alberto eh ricordo. Purtroppo non ho ora vicino queste storie... Vien voglia di rileggerle prima della fine del mondo
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"Fai le cose difficili
quando sono facili,
e inizia le grandi cose
quando sono piccole."(Lao Tzu)
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@G3rt se è vero quel che dice, indica che la società americana si è trasformata in una società fondamentalista religiosa votata all'Armageddon, molto più pericolosa di 100 Isis, che vuole la fine del mondo e ha sotto il proprio controllo l'intero arsenale nucleare
Spero di no
Quel che credo è che sia stato fatto un rovesciamento, se non in colpo di stato in America, e vedremo alle prossime elezioni di mid term se e cosa è vero, se ad esempio dovessero perdere e come reagiranno
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When creating PDFs, avoid using "Print to PDF." A screen reader user may still be able to access the text of PDFs created this way, but heading structure, alternative text, and any other tag structure will be lost. Using "Save As" or "Export" can preserve these tags.
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Referendum. “L’Agcom si riunisce, assolve il Governo e non lo comunica. Dov’è la trasparenza?”
@giornalismo
articolo21.org/2026/03/referen…
L’Osservatorio sulla par condicio del Comitato Società Civile per il NO, in collaborazione con Articolo21
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@Gina I agree. I miss my previous dog a lot.
