Added obsolete syntax
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Dylan Araps
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README.md
316
README.md
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@ -85,19 +85,10 @@ scripts and not full blown utilities.
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* [Arithmetic](#arithmetic)
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* [Simpler syntax to set variables.](#simpler-syntax-to-set-variables)
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* [Ternary tests.](#ternary-tests)
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* [Colors](#colors)
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* [Convert a hex color to RGB.](#convert-a-hex-color-to-rgb)
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* [Convert an RGB color to hex.](#convert-an-rgb-color-to-hex)
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* [Information about the terminal](#information-about-the-terminal)
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* [Get the terminal size in lines and columns (*from a script*).](#get-the-terminal-size-in-lines-and-columns-from-a-script)
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* [Get the terminal size in pixels.](#get-the-terminal-size-in-pixels)
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* [Get the current cursor position.](#get-the-current-cursor-position)
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* [Code Golf](#code-golf)
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* [Shorter `for` loop syntax.](#shorter-for-loop-syntax)
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* [Shorter infinite loops.](#shorter-infinite-loops)
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* [Shorter function declaration.](#shorter-function-declaration)
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* [Shorter `if` syntax.](#shorter-if-syntax)
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* [Simpler `case` statement to set variable.](#simpler-case-statement-to-set-variable)
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* [Obsolete Syntax](#obsolete-syntax)
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* [Shebang.](#shebang)
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* [Command Substitution.](#command-substitution)
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* [Function Declaration.](#function-declaration)
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* [Internal Variables](#internal-variables)
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* [Get the location to the `bash` binary.](#get-the-location-to-the-bash-binary)
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* [Get the version of the current running `bash` process.](#get-the-version-of-the-current-running-bash-process)
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@ -108,6 +99,19 @@ scripts and not full blown utilities.
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* [Get the name of the Operating System / Kernel.](#get-the-name-of-the-operating-system--kernel)
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* [Get the current working directory.](#get-the-current-working-directory)
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* [Get the number of seconds the script has been running.](#get-the-number-of-seconds-the-script-has-been-running)
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* [Information about the terminal](#information-about-the-terminal)
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* [Get the terminal size in lines and columns (*from a script*).](#get-the-terminal-size-in-lines-and-columns-from-a-script)
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* [Get the terminal size in pixels.](#get-the-terminal-size-in-pixels)
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* [Get the current cursor position.](#get-the-current-cursor-position)
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* [Colors](#colors)
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* [Convert a hex color to RGB.](#convert-a-hex-color-to-rgb)
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* [Convert an RGB color to hex.](#convert-an-rgb-color-to-hex)
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* [Code Golf](#code-golf)
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* [Shorter `for` loop syntax.](#shorter-for-loop-syntax)
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* [Shorter infinite loops.](#shorter-infinite-loops)
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* [Shorter function declaration.](#shorter-function-declaration)
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* [Shorter `if` syntax.](#shorter-if-syntax)
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* [Simpler `case` statement to set variable.](#simpler-case-statement-to-set-variable)
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* [Other](#other)
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* [Use `read` as an alternative to the `sleep` command.](#use-read-as-an-alternative-to-the-sleep-command)
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* [Check if a program is in the user's PATH.](#check-if-a-program-is-in-the-users-path)
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@ -916,47 +920,144 @@ Downloads
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((var=var2>var?var2:var))
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```
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# Colors
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# Obsolete Syntax
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## Convert a hex color to RGB.
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## Shebang.
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**Example Function:**
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Use `#!/usr/bin/env bash` instead of `#!/bin/bash`.
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```sh
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hex_to_rgb() {
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# Usage: hex_to_rgb "#FFFFFF"
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((r=16#${1:1:2}))
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((g=16#${1:3:2}))
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((b=16#${1:5:6}))
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- The former searches the user's `PATH` to find the `bash` binary.
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- The latter assumes it is always installed to `/bin/` which can cause issues.
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printf '%s\n' "$r $g $b"
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```shell
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# Right:
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#!/usr/bin/env bash
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# Wrong:
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#!/bin/bash
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```
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## Command Substitution.
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Use `$()` instead of `` ` ` ``.
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```shell
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# Right.
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var="$(command)"
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# Wrong.
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var=`command`
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# $() can easily be nested whereas `` cannot.
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var="$(command "$(command)")"
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```
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## Function Declaration.
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Don't use the `function` keyword, it reduces compatibility with older versions of `bash`.
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```shell
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# Right.
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do_something() {
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# ...
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}
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# Wrong.
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function do_something() {
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# ...
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}
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```
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**Example Usage:**
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# Internal Variables
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**NOTE**: This list does not include every internal variable (*You can
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help by adding a missing entry!*).
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For a complete list, see:
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http://tldp.org/LDP/abs/html/internalvariables.html
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## Get the location to the `bash` binary.
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```shell
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$ hex_to_rgb "#FFFFFF"
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255 255 255
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"$BASH"
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```
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## Convert an RGB color to hex.
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**Example Function:**
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```sh
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rgb_to_hex() {
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# Usage: rgb_to_hex "r" "g" "b"
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printf '#%02x%02x%02x\n' "$1" "$2" "$3"
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}
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```
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**Example Usage:**
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## Get the version of the current running `bash` process.
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```shell
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$ rgb_to_hex "255" "255" "255"
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#FFFFFF
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# As a string.
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"$BASH_VERSION"
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# As an array.
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"${BASH_VERSINFO[@]}"
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```
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## Open the user's preferred text editor.
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```shell
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"$EDITOR" "$file"
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# NOTE: This variable may be empty, set a fallback value.
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"${EDITOR:-vi}" "$file"
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```
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## Get the name of the current function.
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```shell
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# Current function.
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"${FUNCNAME[0]}"
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# Parent function.
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"${FUNCNAME[1]}"
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# So on and so forth.
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"${FUNCNAME[2]}"
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"${FUNCNAME[3]}"
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# All functions including parents.
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"${FUNCNAME[@]}"
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```
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## Get the host-name of the system.
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```shell
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"$HOSTNAME"
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# NOTE: This variable may be empty.
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# Optionally set a fallback to the hostname command.
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"${HOSTNAME:-$(hostname)}"
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```
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## Get the architecture of the Operating System.
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```shell
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"$HOSTTYPE"
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```
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## Get the name of the Operating System / Kernel.
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This can be used to add conditional support for different Operating
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Systems without needing to call `uname`.
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```shell
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"$OSTYPE"
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```
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## Get the current working directory.
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This is an alternative to the `pwd` built-in.
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```shell
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"$PWD"
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```
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## Get the number of seconds the script has been running.
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```shell
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"$SECONDS"
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```
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# Information about the terminal
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@ -1037,6 +1138,50 @@ $ get_cursor_pos
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1 8
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```
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# Colors
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## Convert a hex color to RGB.
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**Example Function:**
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```sh
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hex_to_rgb() {
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# Usage: hex_to_rgb "#FFFFFF"
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((r=16#${1:1:2}))
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((g=16#${1:3:2}))
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((b=16#${1:5:6}))
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printf '%s\n' "$r $g $b"
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}
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```
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**Example Usage:**
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```shell
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$ hex_to_rgb "#FFFFFF"
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255 255 255
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```
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## Convert an RGB color to hex.
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**Example Function:**
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```sh
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rgb_to_hex() {
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# Usage: rgb_to_hex "r" "g" "b"
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printf '#%02x%02x%02x\n' "$1" "$2" "$3"
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}
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```
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**Example Usage:**
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```shell
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$ rgb_to_hex "255" "255" "255"
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#FFFFFF
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```
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# Code Golf
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## Shorter `for` loop syntax.
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@ -1138,95 +1283,6 @@ esac
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os="$_"
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```
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# Internal Variables
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**NOTE**: This list does not include every internal variable (*You can
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help by adding a missing entry!*).
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For a complete list, see:
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http://tldp.org/LDP/abs/html/internalvariables.html
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## Get the location to the `bash` binary.
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```shell
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"$BASH"
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```
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## Get the version of the current running `bash` process.
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```shell
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# As a string.
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"$BASH_VERSION"
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# As an array.
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"${BASH_VERSINFO[@]}"
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```
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## Open the user's preferred text editor.
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```shell
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"$EDITOR" "$file"
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# NOTE: This variable may be empty, set a fallback value.
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"${EDITOR:-vi}" "$file"
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```
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## Get the name of the current function.
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```shell
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# Current function.
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"${FUNCNAME[0]}"
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# Parent function.
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"${FUNCNAME[1]}"
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# So on and so forth.
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"${FUNCNAME[2]}"
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"${FUNCNAME[3]}"
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# All functions including parents.
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"${FUNCNAME[@]}"
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```
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## Get the host-name of the system.
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```shell
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"$HOSTNAME"
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# NOTE: This variable may be empty.
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# Optionally set a fallback to the hostname command.
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"${HOSTNAME:-$(hostname)}"
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```
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## Get the architecture of the Operating System.
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```shell
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"$HOSTTYPE"
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```
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## Get the name of the Operating System / Kernel.
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This can be used to add conditional support for different Operating
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Systems without needing to call `uname`.
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```shell
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"$OSTYPE"
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```
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## Get the current working directory.
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This is an alternative to the `pwd` built-in.
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```shell
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"$PWD"
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```
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## Get the number of seconds the script has been running.
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```shell
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"$SECONDS"
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```
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# Other
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## Use `read` as an alternative to the `sleep` command.
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