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Questions tagged [posix]

POSIX is an acronym for Portable Operating System Interface, a set of standards defining programming APIs and utility behavior for Unix-like operating systems.

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Detecting the total amount of RAM installed on a hardware from a Linux system using a POSIX shell script

Today, I gave myself a small task of detecting the total amount of RAM installed on a hardware from a Linux system using a POSIX shell script. I ended up using ...
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Shell POSIX OpenSSL file decryption script follow-up #3 (final)

From original very simplistic code: Shell POSIX OpenSSL file decryption script I learned a lot both from the first follow-up review, and the second one as well, many thanks! I just need one final ...
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Shell POSIX OpenSSL file decryption script follow-up #2

This question is the second follow-up of: Shell POSIX OpenSSL file decryption script The first follow-up was: Shell POSIX OpenSSL file decryption script follow-up #1 Both of which have proven very ...
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Create a C style char** from a C++ vector<string>

I am dealing with some older C style APIs, like Posix execve that take a char**. In the rest of my code, I prefer to use a ...
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1answer
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Generic error handler function for POSIX shell scripts

Intention I came with the idea of generic, portable, highly reliable, and further customizable function for Shell scripts, written in POSIX, for error handling. Purpose The function shall find out, ...
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2answers
161 views

Long-term archiving + encrypting shell script

Yesterday, I very quickly, in an hour, wrote the very first version of my long-term archiving + encrypting shell script. I am aware it may have too many flaws, but none of them really prevent it from ...
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1answer
127 views

Lightshot Print Screen key linux handler - Follow-up #1

This question is a direct follow-up #1 of my previous question: Lightshot Print Screen key linux handler There were too many errors which I didn't see at the moment and I tried hard to fix them up ...
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3answers
174 views

Calculating linux based octal file permission

I'm applying for a mid level devloper position. In order to progress to 2nd interview, you need to pass a technical test. One of the questions was to write a function to work out linux based octal ...
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1answer
94 views

Lightshot Print Screen key linux handler

I haven't found any Lightshot Print Screen key linux handler publicly available. So, I decided to write one today. It is a standard POSIX shell script. I believe there is always space to get better, ...
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2answers
76 views

Goodgame Empire coin collector with random offsets in (almost-POSIX) Bash

Today, my goal was again to improve my POSIX shell scripting abilities. In one MMO game called Goodgame Empire, there is possible to code yourself a coin (tax) collector. But that's of less ...
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81 views

POSIX shell script for generating pseudo-random numbers

My today's goal was to further practice POSIX shell scripting. So, I decided to write the following POSIX shell script for generating pseudo-random numbers. Any and all reviews would be appreciated. ...
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1answer
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Shell POSIX OpenSSL file decryption script follow-up #1

This question is the first follow-up of: Shell POSIX OpenSSL file decryption script Please read it before you continue reading this. Thank you. I only have one new problem solved and I would like ...
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0answers
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Shell script to manage passwords

To get my feet wet with shell scripting I wrote this "minimal command line password manager" (aka pwm) taking inspiration from the well known ...
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1answer
96 views

Interactive Linux upgrade script

One year ago, I asked for a review of Simple Linux upgrade script in Bash. Conditions are slightly changed, and/or more accurate: Code readability for the code user, making it simple to adjust the ...
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2answers
44 views

How long a PID has been running (taking multiple inputs)

Tonight I tried to write a POSIX shell script which would allow me to check how long a process is running (via it's ID) and be able to handle multiple inputs: ...
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1answer
261 views

Shell POSIX OpenSSL file decryption script

Tonight, I tried to write a Bash OpenSSL file decryption script. Encryption script will follow in highly similar manner, so I think it's not necessary now. Let's suppose we have an encrypted large ...
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1answer
43 views

Implementing POSIX file mode library

I implemented a virtual file system library with POSIX file mode representation. Any suggestions regarding optimization are welcome. ...
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1answer
80 views

Shell script for reading /etc/passwd into SQLite

I want to read 4 columns, namely UID, GID, username and home directory of specific users from /etc/passwd into an SQLite database. I found this to create many ...
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1answer
1k views

C++ wrappers for execv(3)

Calling execv(3) (and similar functions) in C++ can be problematic. execv expects an array of const pointers to non-const ...
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225 views

SIGCONT Handler for terminal application

I'm writing a C++ application for POSIX environment with terminal-based User Interface. I'd like to make my application's UI be consistent between Ctrl-Z and ...
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1answer
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Showing all programs' man pages

I'm trying to discover useful command line tools in Arch Linux, and it seems one good way of going about that is to look through all of the man pages related to ...
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0answers
29 views

Launch and place application depending on screen resolution

I got fed up off opening a set of applications when I wanted to code. So I decided to read up on AppleScript and came up with the following task for myself. Open a application of choice on a given ...
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0answers
99 views

Semaphore implementation by file locking in a bash script

This implementation is inspired by the POSIX functions sem_wait() and sem_post(). It tries to get rid of busy loops in the code ...
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1answer
1k views

Printing infinite loop using pthread [closed]

I'm trying to implement a c program using pthreads which prints "1 2 3 4 5" in an infinite loop. I have used conditional variables and mutex to synchronize the pthreads. I'm able to print "1 2 3 4 5" ...
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1answer
44 views

Split a file into individually allocated lines

This is part of a larger project that is to run on POSIX systems. My concerns with it are the lack of comments, best practices with the filesystem, and naming things. Of course all feedback is great. ...
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1answer
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Running shell commands in a pipeline

I'm writing a shell in C for Linux and BSD. My code was unreadable before but I did a rewrite and now it is much more readable. The purpose of the code is to create a command pipeline and execute it. ...
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1answer
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Creating a struct

Mat told me to create a struct create a struct for the individual commands and arguments. It should have something like the "executable" name, number of args and arg list. Create a few ...
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1answer
70 views

C function for copying array into matrix

I want a matrix that can grow dynamically and build up a structure in RAM as input arrives from standard input och terminal (shell). First I tried with a matrix like ...
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1answer
97 views

Shell command line program

I have refactored a for loop into a function. I'm still a beginner at using C utility functions such as strtok, ...
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1answer
81 views

Makefile and main header file for a shell

My main.c includes this header file. Please let me know how I can improve it. I did my best but I don't know much about code conventions in C (I come from Java and ...
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1answer
103 views

run command pipeline in C

This code parses and tokenizes my shell language command interpreter. I will try and make it 2 functions, one that is the tokenizer and the other that is the rest of the function. Can you find ...
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1answer
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C stack for Linux and BSD

My stack uses char data and is not tested. I use it to save command in a unix pipeline for my own POSIX shell. Maybe you can find a bug or a possible improvement. ...
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1answer
80 views

C main function for POSIX shell

I got a pretty large main function that I want to break up in smaller helper functions. Can you help me suggest what to break out into helper functions? The ...
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1answer
39 views

Handle builtin commands

I've written a small C function to handle the builtin commands of a custom shell that I'm writing in C. Is it better to use a switch instead? ...
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1answer
40 views

C function to find the less program

I've written a C function to find the program less that the operating system should provide. If lessis not provided, some other ...
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1answer
160 views

Recreation of cat in C

I have a school project to create a program that works the same as the Linux cat. The code works, but I just need find out where I can Improve it or handle errors. ...
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1answer
2k views

Multithreaded MJPG network stream server

I'm a bit of a neophyte when it comes to C++, and so I'd like some feedback regarding a recent project. The code sits on a Raspberry Pi and streams camera data over TCP on a specified port. The ...
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2answers
647 views

Colorful output on terminal

I went from manually outputting escape codes in each string to creating a utility struct/class full of static functions and variables that needed to be initialized in source files (static private ...
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1answer
180 views

Subset of UNIX standard tar implementation

I recently implemented a subset of the ustar archiving utility as my first year programming one project. I would like to get it reviewed and if anyone has anything to point out. dir.c ...
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2answers
142 views

Implementation of the ls command with several options - follow-up 2

I've made more improvements from previous iterations and my own, including: Added the -n flag (print owner and group IDs instead of names) Eliminated some ...
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2answers
849 views

Implementation of the ls command with several options - follow-up

I've made vast improvements to my previous ls implementation, including: Added new flags: -g (omit owner listing) ...
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3answers
7k views

Implementation of the ls command with several options

As part of a past assignment, I've expanded on this implementation of ls to have more options available, including non-standard ones. It currently supports these (...
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0answers
68 views

N Processing connect to a single process: Socket Programming

The idea of my program is to use pthreads, semaphores, posix shared memory, and sockets to create an environment where N processes (that we will refer to as the children) can connect to a single ...
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2answers
128 views

Self-written Mutex for 2+ Threads

I have written the following code, and so far in all my tests it seems as if I have written a working Mutex for my 4 Threads, but I would like to get someone else's opinion on the validity of my ...
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1answer
107 views

POSIX shell compatible and POSIX conforming dirname implementation

The discussion in the comments of this answer made me wonder how hard it would be to write a built-in only version of dirname. This is what I ended up with but I'm ...
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2answers
2k views

Fast line-by-line file reader

This is designed for a high performance complex log analyzer. Very simple idea: read a file line-by-line as fast as possible. I would appreciate any hints what should/could be improved in this code. ...
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1answer
66 views

Implementing dirpath(3p) and fdirpath(3p) functions

I'm implementing a dirpath and fdirpath functions, which allow to retrieve path from the directory handle (or its descriptor). ...
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1answer
68 views

Simple file locking wrapper command in C

A simple command that wraps another command, locking a file first. It is similar to flock, just simpler. ...
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1answer
161 views

ttyname() implemented in Go

I'm rewriting GNU's coreutils in Go in order to learn Go better. I've implemented ttyname(3), and I'm looking for a general critique. I can't think of anything in particular I think I did poorly on. (...
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3answers
1k views

Check disk space against a threshold

The below script is one I made to check the disk space on mounted partitions under Debian Wheezy. I tried adding a -d switch to force printing out the used data, ...