diff --git a/README.md b/README.md
index f3c9e35..262e1f2 100644
--- a/README.md
+++ b/README.md
@@ -60,6 +60,12 @@ scripts and not full blown utilities.
     * [Check if string ends with sub-string.](#check-if-string-ends-with-sub-string)
 * [Variables](#variables)
     * [Assign and access a variable using a variable.](#assign-and-access-a-variable-using-a-variable)
+    * [Indirection](#indirection)
+    * [Replacement](#replacement)
+    * [Length](#length)
+    * [Expansion](#expansion)
+    * [Case Modification](#case-modification)
+    * [Default Value](#default-value)
 * [Arrays](#arrays)
     * [Reverse an array.](#reverse-an-array)
     * [Remove duplicate array elements.](#remove-duplicate-array-elements)
@@ -489,6 +495,69 @@ var2="hello_${var1}"
 printf '%s\n' "${!var2}"
 ```
 
+## Indirection
+
+| Parameter | What does it do? |
+| --------- | ---------------- |
+| `${!VAR}` | Access a variable based on the value of `VAR`. See: [link](#assign-and-access-a-variable-using-a-variable)
+| `${!VAR*}` | Expand to `IFS` separated list of variable names starting with `VAR`. |
+| `${!VAR@}` | Expand to `IFS` separated list of variable names starting with `VAR`. |
+
+
+## Replacement
+
+| Parameter | What does it do? |
+| --------- | ---------------- |
+| `${VAR#PATTERN}` | Remove shortest match of pattern from start of string. |
+| `${VAR##PATTERN}` | Remove longest match of pattern from start of string. |
+| `${VAR%PATTERN}` | Remove shortest match of pattern from end of string. |
+| `${VAR%%PATTERN}` | Remove longest match of pattern from end of string. |
+| `${VAR/PATTERN/REPLACE}` | Replace first match with string.
+| `${VAR//PATTERN/REPLACE}` | Replace all matches with string.
+| `${VAR/PATTERN}` | Remove first match.
+| `${VAR//PATTERN}` | Remove all matches.
+
+## Length
+
+| Parameter | What does it do? |
+| --------- | ---------------- |
+| `${#VAR}` | Length of var in characters.
+| `${#ARR[@]}` | Length of array in elements.
+
+## Expansion
+
+| Parameter | What does it do? |
+| --------- | ---------------- |
+| `${VAR:OFFSET}` | Remove first `N` chars from variable.
+| `${VAR:OFFSET:LENGTH}` | Get substring from `N` character to `N` character. <br> (`${VAR:10:10}`: Get sub-string from char `10` to char `20`)
+| `${VAR:: OFFSET}` | Get first `N` chars from variable.
+| `${VAR:: -OFFSET}` | Remove last `N` chars from variable.
+| `${VAR: -OFFSET}` | Get last `N` chars from variable.
+| `${VAR:OFFSET:-OFFSET}` | Cut first `N` chars and last `N` chars. | `bash 4.2+` |
+
+## Case Modification
+
+| Parameter | What does it do? | CAVEAT |
+| --------- | ---------------- | ------ |
+| `${VAR^}` | Uppercase first character. | `bash 4+` |
+| `${VAR^^}` | Uppercase all characters. | `bash 4+` |
+| `${VAR,}` | Lowercase first character. | `bash 4+` |
+| `${VAR,,}` | Lowercase all characters. | `bash 4+` |
+
+
+## Default Value
+
+| Parameter | What does it do? |
+| --------- | ---------------- |
+| `${VAR:-STRING}` | If `VAR` is empty or unset, use `STRING` as it's value.
+| `${VAR-STRING}` | If `VAR` is unset, use `STRING` as it's value.
+| `${VAR:=STRING}` | If `VAR` is empty or unset, set the value of `VAR` to `STRING`.
+| `${VAR=STRING}` | If `VAR` is unset, set the value of `VAR` to `STRING`.
+| `${VAR:+STRING}` | If `VAR` isn't empty, use `STRING` as it's value.
+| `${VAR+STRING}` | If `VAR` is set, use `STRING` as it's value.
+| `${VAR:?STRING}` | Display an error if empty or unset.
+| `${VAR?STRING}` | Display an error if unset.
+
 
 # Arrays