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Dylan Araps
2018-06-13 12:35:53 +10:00
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@@ -20,20 +20,119 @@ list, send a pull request!
<!-- vim-markdown-toc GFM --> <!-- vim-markdown-toc GFM -->
* [Getting the terminal size (*in a script*).](#getting-the-terminal-size-in-a-script) * [File handling](#file-handling)
* [Get the current date using `strftime`.](#get-the-current-date-using-strftime) * [Get the first N lines in a file.](#get-the-first-n-lines-in-a-file)
* [Get the first N lines in a file.](#get-the-first-n-lines-in-a-file) * [Get the last N lines in a file.](#get-the-last-n-lines-in-a-file)
* [Get the last N lines in a file.](#get-the-last-n-lines-in-a-file) * [Get the number of lines in a file.](#get-the-number-of-lines-in-a-file)
* [Get the number of lines in a file.](#get-the-number-of-lines-in-a-file) * [Strings](#strings)
* [Get the directory name of a file path.](#get-the-directory-name-of-a-file-path) * [Get the directory name of a file path.](#get-the-directory-name-of-a-file-path)
* [Convert a hex color to RGB](#convert-a-hex-color-to-rgb) * [Trim quotes from a string.](#trim-quotes-from-a-string)
* [Convert an RGB color to hex.](#convert-an-rgb-color-to-hex) * [Colors](#colors)
* [Trim quotes from a string.](#trim-quotes-from-a-string) * [Convert a hex color to RGB](#convert-a-hex-color-to-rgb)
* [Convert an RGB color to hex.](#convert-an-rgb-color-to-hex)
* [Miscellaneous](#miscellaneous)
* [Getting the terminal size (*in a script*).](#getting-the-terminal-size-in-a-script)
* [Get the current date using `strftime`.](#get-the-current-date-using-strftime)
<!-- vim-markdown-toc --> <!-- vim-markdown-toc -->
## Getting the terminal size (*in a script*). ## File handling
### Get the first N lines in a file.
Alternative to the `head` command.
**NOTE:** Requires `bash` 4+
```sh
head() {
# Usage: head "n" "file"
mapfile -tn "$1" line < "$2"
printf '%s\n' "${line[@]}"
}
```
### Get the last N lines in a file.
Alternative to the `tail` command.
**NOTE:** Requires `bash` 4+
```sh
tail() {
# Usage: tail "n" "file"
mapfile -tn 0 line < "$2"
printf '%s\n' "${line[@]: -$1}"
}
```
### Get the number of lines in a file.
Alternative to `wc -l`.
**NOTE:** Requires `bash` 4+
```sh
lines() {
# Usage lines "file"
mapfile -tn 0 lines < "$1"
printf '%s\n' "${#lines[@]}"
}
```
## Strings
### Get the directory name of a file path.
Alternative to the `dirname` command.
```sh
dirname() {
# Usage: dirname "path"
printf '%s\n' "${1%/*}/"
}
```
### Trim quotes from a string.
```sh
trim_quotes() {
# Usage: trim_quotes "string"
: "${1//\'}"
printf "%s\\n" "${_//\"}"
}
```
## Colors
### Convert a hex color to RGB
```sh
hex_to_rgb() {
# Usage: hex_to_rgb "#FFFFFF"
((r=16#${1:1:2}))
((g=16#${1:3:2}))
((b=16#${1:5:6}))
printf '%s\n' "$r $g $b"
}
```
### Convert an RGB color to hex.
```sh
rgb_to_hex() {
# Usage: rgb_to_hex "r" "g" "b"
printf '#%02x%02x%02x\n' "$1" "$2" "$3"
}
```
## Miscellaneous
### Getting the terminal size (*in a script*).
This is handy when writing scripts in pure bash and `stty`/`tput` can’t be This is handy when writing scripts in pure bash and `stty`/`tput` can’t be
called. called.
@@ -50,7 +149,7 @@ get_term_size() {
``` ```
## Get the current date using `strftime`. ### Get the current date using `strftime`.
Bash’s `printf` has a built-in method of getting the date which we can use Bash’s `printf` has a built-in method of getting the date which we can use
in place of the `date` command in a lot of cases. in place of the `date` command in a lot of cases.
@@ -66,87 +165,3 @@ date() {
``` ```
## Get the first N lines in a file.
Alternative to the `head` command.
**NOTE:** Requires `bash` 4+
```sh
head() {
# Usage: head "n" "file"
mapfile -tn "$1" line < "$2"
printf '%s\n' "${line[@]}"
}
```
## Get the last N lines in a file.
Alternative to the `tail` command.
**NOTE:** Requires `bash` 4+
```sh
tail() {
# Usage: tail "n" "file"
mapfile -tn 0 line < "$2"
printf '%s\n' "${line[@]: -$1}"
}
```
## Get the number of lines in a file.
Alternative to `wc -l`.
**NOTE:** Requires `bash` 4+
```sh
lines() {
# Usage lines "file"
mapfile -tn 0 lines < "$1"
printf '%s\n' "${#lines[@]}"
}
```
## Get the directory name of a file path.
Alternative to the `dirname` command.
```sh
dirname() {
# Usage: dirname "path"
printf '%s\n' "${1%/*}/"
}
```
## Convert a hex color to RGB
```sh
hex_to_rgb() {
# Usage: hex_to_rgb "#FFFFFF"
((r=16#${1:1:2}))
((g=16#${1:3:2}))
((b=16#${1:5:6}))
printf '%s\n' "$r $g $b"
}
```
## Convert an RGB color to hex.
```sh
rgb_to_hex() {
# Usage: rgb_to_hex "r" "g" "b"
printf '#%02x%02x%02x\n' "$1" "$2" "$3"
}
```
## Trim quotes from a string.
```sh
trim_quotes() {
# Usage: trim_quotes "string"
: "${1//\'}"
printf "%s\\n" "${_//\"}"
}
```