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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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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.
Advanced Programming in the UNIX Environment
Week 4: Directories
In this video lecture, we take a look at how directories are created and removed, as well as how to move around the filesystem hierarchy. We also learn why the 'cd' command must be a shell builtin in order to work.
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Advanced Programming in the UNIX Environment
Week 4: Directories
In this video lecture, we take a look at how directories are created and removed, as well as how to move around the filesystem hierarchy. We also learn why the 'cd' command must be a shell builtin in order to work.
Advanced Programming in the UNIX Environment
Week 4: Directory Size
In this video lecture, we dive deep into the structure of the directory on a traditional Unix File System and see how its size is independent of the file sizes of its entries, but dependent on the filename lengths. We'll also use hexdump(1) to cheat a bit and look at the directory structure on disk.
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Advanced Programming in the UNIX Environment
Week 4: Directory Size
In this video lecture, we dive deep into the structure of the directory on a traditional Unix File System and see how its size is independent of the file sizes of its entries, but dependent on the filename lengths. We'll also use hexdump(1) to cheat a bit and look at the directory structure on disk.
Advanced Programming in the UNIX Environment
Week 4: /etc/passwd
In this short video, we try to answer the awkward question "Mommy, where do UIDs come from?". We look at the /etc/passwd user database and identify the various fields before we look at how things can get weird.
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Advanced Programming in the UNIX Environment
Week 4: /etc/passwd
In this short video, we try to answer the awkward question "Mommy, where do UIDs come from?". We look at the /etc/passwd user database and identify the various fields before we look at how things can get weird.
Advanced Programming in the UNIX Environment
Week 4: getpwuid(2) and /etc/groups
In this video lecture, we look at the library functions used to look up account information. We learn about how primary and supplementary groups are handled as well as how the hashed passwords are stored outside of the world readable /etc/passwd file.
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Advanced Programming in the UNIX Environment
Week 4: getpwuid(2) and /etc/groups
In this video lecture, we look at the library functions used to look up account information. We learn about how primary and supplementary groups are handled as well as how the hashed passwords are stored outside of the world readable /etc/passwd file.
Advanced Programming in the UNIX Environment
Week 4: atime, mtime, ctime
In this video lecture, we start looking a little bit closer into what our systems think of "time", something that experts most accurately describe as a big ball of wibbly, wobbly, timey, wimey... stuff. In short, analyze how the atime, mtime, and ctimes of a file connect.
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Advanced Programming in the UNIX Environment
Week 4: atime, mtime, ctime
In this video lecture, we start looking a little bit closer into what our systems think of "time", something that experts most accurately describe as a big ball of wibbly, wobbly, timey, wimey... stuff. In short, analyze how the atime, mtime, and ctimes of a file connect.
Advanced Programming in the UNIX Environment
Week 4: time(3) is an illusion
Having revisited the atime, mtime, and time in our last video segment, we now have to come to terms with time(3) itself. We'll discuss managing the data structures and handling arbitrary concepts such as leap seconds, timezones, and (ugh) Daylight Savings Time. It gets silly real quick.
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Advanced Programming in the UNIX Environment
Week 4: time(3) is an illusion
Having revisited the atime, mtime, and time in our last video segment, we now have to come to terms with time(3) itself. We'll discuss managing the data structures and handling arbitrary concepts such as leap seconds, timezones, and (ugh) Daylight Savings Time. It gets silly real quick.
Related to our discussion of time(3), here's a deeper dive into the Unix epoch, its origins, and how the Y2K38 issue actually affects different unix systems well before the heat-death of the universe.
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Related to our discussion of time(3), here's a deeper dive into the Unix epoch, its origins, and how the Y2K38 issue actually affects different unix systems well before the heat-death of the universe.
Advanced Programming in the Unix Environment
Week 5: The Unix Development Environment
This week, we cover the concept of the Unix userland as an Integrated Development Environment. This introduction outlines the different tools we will cover in subsequent videos, including the editor, the compiler chain, make(1), the debugger, and code revision and management tools. No vibe coding here.
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Advanced Programming in the Unix Environment
Week 5: The Unix Development Environment
This week, we cover the concept of the Unix userland as an Integrated Development Environment. This introduction outlines the different tools we will cover in subsequent videos, including the editor, the compiler chain, make(1), the debugger, and code revision and management tools. No vibe coding here.
Advanced Programming in the Unix Environment
Week 5: The Editor
In this video lecture, we look at the required feature for a full-fledged programmer's editor and illustrate some of the core functionality by example of vim(1). This includes basic motion commands, setting and moving to markers, using folds, and the use of the ':make' and quick fix lists to address compiler errors efficiently.
(Don't worry, we'll talk about ed(1) later.)
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Advanced Programming in the Unix Environment
Week 5: The Editor
In this video lecture, we look at the required feature for a full-fledged programmer's editor and illustrate some of the core functionality by example of vim(1). This includes basic motion commands, setting and moving to markers, using folds, and the use of the ':make' and quick fix lists to address compiler errors efficiently.
(Don't worry, we'll talk about ed(1) later.)
Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part I
In this video lecture, we begin our discussion of compilers as part of the Unix programming environment. We provide a high-level overview of how compilers process input source code and turn it into an executable.
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Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part I
In this video lecture, we begin our discussion of compilers as part of the Unix programming environment. We provide a high-level overview of how compilers process input source code and turn it into an executable.
Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part II
In this video lecture, we look at the preprocessing stage of the compiler and observe how it invokes the cpp(1) command to include header files or replace macro definitions in place.
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Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part II
In this video lecture, we look at the preprocessing stage of the compiler and observe how it invokes the cpp(1) command to include header files or replace macro definitions in place.
Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part III
In this next-to-last part on the compiler chain, we look at the compilation proper and the optimization and assembly of the intermediate code into an object file. (We will revisit some of this when we take a closer look at shared libraries in week 11.)
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Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part III
In this next-to-last part on the compiler chain, we look at the compilation proper and the optimization and assembly of the intermediate code into an object file. (We will revisit some of this when we take a closer look at shared libraries in week 11.)
Advanced Programming in the Unix Environment
Week 5: The Compiler Chain, Part IV
In this video lecture, we conclude our discussion of the compiler chain, analyzing the last step in the process: linking the object files into the executable. We identify aspects of the C Runtime libraries as well as the standard C library that we need to include and cover a few of the most important flags to ld(1).
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Gli ultimi otto messaggi ricevuti dalla Federazione
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My youngest dog always walks around the house and back yard like he's ancient. Like, wobbling along like he's in pain, kinda limping. But, when we're on a walk or he's off-lead in the forest, he's like a rocket, absolutely full-tilt 100% of the time, not a care in the world, no think just run. No trace of a limp, seemingly no problems.
I think he's just really lazy when he's somewhere boring? Like a sullen teenager ambling through the halls at school.
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Al posto di Gassman per interpretare l'avvocato Guerrieri sarebbe stato meglio
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Point of order.
CAMH in Houston is:
https://en.wikipedia.org/wiki/Contemporary_Arts_Museum_Houston
CAMH in Toronto is:
https://en.wikipedia.org/wiki/Centre_for_Addiction_and_Mental_Health
You were possibly thinking of this other Toronto institution?
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@marble Bean,
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@mcc Tbh the bean could be anything and people would still want to come to see it. Weird how that works lol.
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@mcc
It’s breaking my brain on a budget.
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@cretinodicrescenzago @enverdemichelis @las_lallero @francommit
Ora che finalmente conosciamo e coltiviamo i kumquat è arrivato finalmente il tempo dello sdoganamento... 😂😂
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@mcc some bean flicking
