# Luscii Terraform Fluentbit Config Renderer Terraform Regex Patterns > Terraform Regex Patterns Skill - Skill: `tomevault-io/luscii-terraform-fluentbit-config-renderer-terraform-regex-p` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/luscii-terraform-fluentbit-config-renderer-terraform-regex-p` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/luscii-terraform-fluentbit-config-renderer-terraform-regex-p/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: DevOps & Infra - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/luscii-terraform-fluentbit-config-renderer-terraform-regex-p --- # Terraform Regex Patterns Skill ## Overview This skill provides a curated set of regular expression (regex) patterns and usage examples for use with Terraform's built-in regex functions: - `regex(pattern, string)` - `regexall(pattern, string)` - `replace(string, substring/pattern, replacement)` It also covers syntax, sequences, and flags as documented in the [Terraform regex function documentation](https://developer.hashicorp.com/terraform/language/functions/regex). --- ## Syntax and Flags Terraform uses [RE2 syntax](https://github.com/google/re2/wiki/Syntax). Flags are set inline in the pattern, e.g. `(?i)` for case-insensitive. ### Sequences | Sequence | Description | |------------------|------------------------------------------------------------------| | `.` | any character except newline | | `^` | start of string | | `$` | end of string | | `*` | zero or more | | `+` | one or more | | `?` | zero or one | | `[...]` | character class | | `[xyz]` | any character listed between the brackets (`x`, `y`, `z`) | | `[^xyz]` | any character except those listed between the brackets | | `(...)` | capture group | | `\d` | ASCII digits `[0-9]` | | `\D` | anything except ASCII digits | | `\w` | word character `[0-9A-Za-z_]` | | `\W` | anything except the characters matched by `\w` | | `\s` | whitespace | | `[[:alnum:]]` | same as `[0-9A-Za-z]` | | `[[:alpha:]]` | same as `[A-Za-z]` | | `[[:ascii:]]` | any ASCII character | | `[[:blank:]]` | ASCII tab or space | | `[[:cntrl:]]` | ASCII/Unicode control characters | | `[[:digit:]]` | same as `[0-9]` | | `[[:graph:]]` | all "graphical" (printable) ASCII characters | | `[[:lower:]]` | same as `[a-z]` | | `[[:print:]]` | same as `[[:graph:]]` | | `[[:punct:]]` | same as `[!-/:-@[-`{-~]` | | `[[:space:]]` | same as `[\t\n\v\f\r ]` | | `[[:upper:]]` | same as `[A-Z]` | | `[[:word:]]` | same as `\w` | | `[[:xdigit:]]` | same as `[0-9A-Fa-f]` | ### Flags Some of the matching behaviors described above can be modified by setting matching flags, activated using either the (?flags) operator (to activate within the current sub-pattern) or the (?flags:x) operator (to match x with the modified flags). Each flag is a single letter, and multiple flags can be set at once by listing multiple letters in the flags position. The available flags are listed in the table below: | Flag | Meaning | | `i` | Case insensitive: a literal letter in the pattern matches both lowercase and uppercase versions of that letter | | `m` | The ^ and $ operators also match the beginning and end of lines within the string, marked by newline characters; behavior of `\A` and `\z` is unchanged | | `s` | The `.` operator also matches newline | | `U` | The meaning of presence or absense `?` after a repetition operator is inverted. For example, `x*` is interpreted like `x*?` and vice-versa. | --- ## Usage Examples ### Validate Email Address ```hcl regex("^[\w._%+-]+@[\w.-]+\\.[a-zA-Z]{2,}$", var.email) ``` ### Extract Digits from String ```hcl regexall("\\d+", var.input) ``` ### Replace All Whitespace with Dash ```hcl replace(var.input, "\\s+", "-") ``` ### Match AWS ARN ```hcl regex("^arn:aws:[a-z0-9-]+:[a-z0-9-]*:[0-9]*:.*$", var.arn) ``` ### Case-Insensitive Match ```hcl regex("(?i)^prod$", var.env) ``` ### Extract Lowercase Letters from String ```hcl regex("[a-z]+", "53453453.345345aaabbbccc23454") # returns: aaabbbccc ``` ### Extract Date Parts from String ```hcl regexall("\\d+", "2019-02-01") # returns: ["2019", "02", "01"] ``` ### Parse URL Scheme and Authority ```hcl regex("^(?:(?P[^:/?#]+):)?(?://(?P[^/?#]*))?", "https://terraform.io/docs/") # returns: { "authority" = "terraform.io", "scheme" = "https" } ``` ### Error: Pattern Did Not Match ```hcl regex("[a-z]+", "53453453.34534523454") # error: pattern did not match any part of the given string ``` --- ## Pattern Library | Pattern | Description | Example | |---------|-------------|---------| | `^prod$` | Exact match for "prod" | `regex("^prod$", var.env)` | | `(?i)^dev$` | Case-insensitive "dev" | `regex("(?i)^dev$", var.env)` | | `^\d{4}-\d{2}-\d{2}$` | Date YYYY-MM-DD | `regex("^\d{4}-\d{2}-\d{2}$", var.date)` | | `^[a-zA-Z0-9_-]+$` | Alphanumeric, dash, underscore | `regex("^[a-zA-Z0-9_-]+$", var.name)` | | `^arn:aws:[a-z0-9-]+:[a-z0-9-]*:[0-9]*:.*$` | AWS ARN | `regex("^arn:aws:[a-z0-9-]+:[a-z0-9-]*:[0-9]*:.*$", var.arn)` | | `(?i)error|fail|critical` | Match error keywords (case-insensitive) | `regex("(?i)error|fail|critical", var.log)` | | `^\s*$` | Empty or whitespace | `regex("^\s*$", var.input)` | --- ## References - [Terraform regex function](https://developer.hashicorp.com/terraform/language/functions/regex) - [RE2 syntax](https://github.com/google/re2/wiki/Syntax) --- ## How to Use - Use these patterns directly in `regex`, `regexall`, or `replace` functions in Terraform. - Adjust patterns as needed for your use case. - For complex validation, combine multiple patterns or use `regexall` for all matches. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/luscii) — claim your Tome and manage your conversions.