Linked Questions
22 questions linked to/from What is the difference between a builtin command and one that is not?
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Why is my CD command not working on a home-built shell? [duplicate]
I have written a very basic shell in C. It reads the input, then runs it using system(lineCopy); (lineCopy being a copy of the input). All commands will run fine in it, other than cd. When I try to cd ...
user102473
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What is the difference between test, [, and [[ in terms of binary vs. builtin? [duplicate]
It is often written:
/usr/bin/test is a synonym for /usr/bin/[
[[ is a bash improvement for [
test and [ are also builtins
I understand the difference between [ and [[ but I am confused with the ...
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Why is cd not a program?
I've always wondered why cd isn't a program, but never managed to find the answer.
Anyone know why this is the case?
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What exactly is POSIX?
I see POSIX mentioned often and everywhere, and I had assumed it to be the baseline UNIX standard.. until I noticed the following excerpt on a Wikipedia page: The Open Group
The Open Group is ...
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What is the difference between interactive shells, login shells, non-login shell and their use cases? [duplicate]
Possible Duplicate:
Difference between Login Shell and Non-Login Shell?
I have been looking at /etc/profile. bash.bashrc to see how they are run, and notice that some are executed by non-login ...
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Why are POSIX mandatory utilities not built into the shell?
The purpose of this question is to answer a curiosity, not to solve a particular computing problem. The question is: Why are POSIX mandatory utilities not commonly built into shell implementations?
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How do you time how long a command took to run? [duplicate]
How would you find out how long a running process took to complete?
Example:
date; dd bs=1m if=/foo of=bar; date
^This example only has 1 second of resolution.
Any shell is acceptable.
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What is the purpose of square bracket executable
I see there is an executable called "[" in /usr/bin. What is its purpose?
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How are system commands like ls created?
I have some doubts regarding *nix.
I don't know which type of executable file is ls, whether it is .sh
or .ksh or any other kind of system executable if it is, what
is that?
when I tried to see what ...
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IFS=',' /usr/bin/read vs IFS=',' read
Context
$ bash --version
GNU bash, version 4.4.19(1)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/...
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Understanding shell builtin commands
In in the bash manual, it's written that
Builtin commands are contained >>> within <<< the shell itself
Also, this answer states that
A built-in command is simply a command that ...
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When are the built-in commands loaded to memory
Let's say if I type in cd in my shell. Is cd loaded from the memory at that moment? My intuition is that these built-in commands are pre-loaded to the system memory after the kernel has been loaded, ...
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Differences between keyword, reserved word, and builtin?
From Make bash use external `time` command rather than shell built-in, Stéphane Chazelas wrote:
There is no time bash builtin. time is a keyword so you can do for instance time { foo; bar; }
We ...
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How to know what are commands, system calls, bash built-ins, etc?
A coworker recently asked "What is man"? After being informed that not all things accessible from the Bash CLI are commands, I was wary to call man a command.
man man just calls it an ...
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Edit tree to output in custom format?
I'd like to get a custom output from the tree command, but unlike this question, I don't have a fixed format. I'd like to be able to give the command the format in an argument (for instance perhaps -f=...
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