Questions tagged [posix]
POSIX is an acronym for Portable Operating System Interface, a family of standards specified by the IEEE for maintaining compatibility between operating systems.
704 questions
4
votes
3
answers
291
views
Help w/ "posix-extended" regex for 'find'
Can someone explain the issue I've described below, and perhaps suggest a resolution?
I'm trying to process a set of filenames using find. My platform is macOS (Ventura 13.7.7), and the shell is zsh ...
- 3,833
0
votes
0
answers
26
views
Posix filesystem features overlay [duplicate]
I have a remote system where I can create only files and directories. No symlinks, ACLs, hard links, devices, nothing.
I think, it would be really useful to be able to use it even as a linux root ...
- 10.5k
0
votes
0
answers
47
views
pgrep executable matching specific (current) user only
In a code review on Final look at my Lightshot print screen Linux handler POSIX shell script, specifically in this short answer, it has been pointed out to me, that if there are multiple X servers ...
- 31.1k
7
votes
3
answers
912
views
With `#!/bin/sh`, what is the closest to `;;&` (`bash`'s fallthrough)?
Without ;;&, /bin/sh gives Syntax error: ")" unexpected (expecting ";;").
;;& triggers shellcheck's ^-- SC2127 (error): To use cases with ;;&, specify #!/usr/bin/env ...
- 71
7
votes
1
answer
263
views
Newlines in environment variable names under POSIX sh
This question asks how to get a list of environment variable names in POSIX sh. The top answer suggests invoking awk via the shell, but gives this caveat:
The output is ambiguous if the name of an ...
- 365
14
votes
1
answer
868
views
Does POSIX guarantee that awk programs with only a BEGIN action won't read stdin?
Consider this awk invocation:
awk 'BEGIN {print 1}'
There are no input files, so stdin is used for input. However, the program only contains a BEGIN pattern, so there is no need to read it. Does ...
- 365
1
vote
0
answers
50
views
setfacl on Cygwin always returns "permission denied"
I apologize in advance if this isn't the right forum to post this, but since it's a Linux tool on an (emulated) Linux platform (and since I saw some other Cygwin-related questions on here) this is the ...
- 111
3
votes
2
answers
138
views
Localising variables in /bin/sh functions
POSIX defines shell functions as:
fname ( ) compound-command [io-redirect ...]
The compound-command is further defined as either:
( compound-list )
{ compound-list ; }
In particular POSIX notes for ...
- 128k
4
votes
1
answer
343
views
POSIX-compliance of NMAKE
NMAKE by Microsoft comes with some components of Visual Studio. Is it POSIX-compliant?
user762210
0
votes
2
answers
85
views
Do race conditions occur during pathname resolution with constant string absolute path literals?
According to The Open Group Base Specifications Issue 8, on the rationale of the open() and openat() functions:
The purpose of the openat() function is to enable opening files in directories other ...
- 1
12
votes
1
answer
942
views
How are specification issues / defects of POSIX collected and how can I participate?
While pondering whether IEEE 1003.1-2017 forbids race-condition safe ln -f, it occurred to me:
Even if this is really an unfortunate definition (which GNU coreutils' ln thankfully ignores), I would ...
- 51.2k
15
votes
3
answers
3k
views
Why Linux read() avoids using full 2 GiB in one call
Reading the manual page (man 2 read) on my Debian system, I see the following note:
NOTES
[...]
On Linux, read() (and similar system calls) will transfer at most
0x7ffff000 (2,147,479,552) bytes, ...
- 3,459
1
vote
4
answers
187
views
Need shell script help - processing the same option multiple times
So I've ran into a bit of a wall, I have an option in my script that calls a function which allows me to specify a file/directory and then I want to parse that output into a menu tool (using dmenu in ...
- 11
2
votes
1
answer
168
views
What is the origin of the -E option of the `realpath` command in POSIX issue 8?
The realpath command utility is now defined by POSIX in its issue 8 (2024): realpath — resolve a pathname
realpath [-E|-e] file
The realpath utility shall canonicalize the pathname specified by the ...
- 1,601
7
votes
2
answers
1k
views
How to find out if a command wrote to stdout or not
I'd like to figure out if an external program ran successfully and wrote something to stdout, or if it did not write anything, which happens in case an error occurred. The program unfortunately always ...
- 3,554