docs: update

README.md

@@ -25,6 +25,9 @@ list, send a pull request!
 * [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)
 * [Convert an RGB color to hex.](#convert-an-rgb-color-to-hex)
+* [Trim quotes from a string.](#trim-quotes-from-a-string)
+* [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)
 
 <!-- vim-markdown-toc -->
 
@@ -94,4 +97,41 @@ rgb_to_hex() {
 }
 ```
 
+## Trim quotes from a string.
 
+```sh
+trim_quotes() {
+    # Usage: trim_quotes "string"
+    : "${1//\'}"
+    printf "%s\\n" "${_//\"}"
+}
+```
+
+
+## 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}"
+}
+```