Update cheatsheets

tldr/gau

@@ -0,0 +1,37 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# gau
+
+> Get All URLs: fetch known URLs from AlienVault's Open Threat Exchange, the Wayback Machine, and Common Crawl for any domains.
+> More information: <https://github.com/lc/gau>.
+
+- Fetch all URLs of a domain from AlienVault's Open Threat Exchange, the Wayback Machine, Common Crawl, and URLScan:
+
+`gau {{example.com}}`
+
+- Fetch URLs of multiple domains:
+
+`gau {{domain1 domain2 ...}}`
+
+- Fetch all URLs of several domains from an input file, running multiple threads:
+
+`gau --threads {{4}} < {{path/to/domains.txt}}`
+
+- Write [o]utput results to a file:
+
+`gau {{example.com}} --o {{path/to/found_urls.txt}}`
+
+- Search for URLs from only one specific provider:
+
+`gau --providers {{wayback|commoncrawl|otx|urlscan}} {{example.com}}`
+
+- Search for URLs from multiple providers:
+
+`gau --providers {{wayback,otx,...}} {{example.com}}`
+
+- Search for URLs within specific date range:
+
+`gau --from {{YYYYMM}} --to {{YYYYMM}} {{example.com}}`

tldr/linux/dhcpcd

@@ -0,0 +1,17 @@
+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# dhcpcd
+
+> DHCP client.
+> More information: <https://roy.marples.name/projects/dhcpcd>.
+
+- Release all address leases:
+
+`sudo dhcpcd --release`
+
+- Request the DHCP server for new leases:
+
+`sudo dhcpcd --rebind`

tldr/shellcheck

@@ -5,34 +5,37 @@ source: https://github.com/tldr-pages/tldr.git
 ---
 # shellcheck
 
-> Shell script static analysis tool.
-> Check shell scripts for errors, usage of deprecated/insecure features, and bad practices.
-> More information: <https://www.shellcheck.net>.
+> Statically check shell scripts for errors, usage of deprecated/insecure features, and bad practices.
+> More information: <https://github.com/koalaman/shellcheck/wiki>.
 
 - Check a shell script:
 
 `shellcheck {{path/to/script.sh}}`
 
-- Check a shell script interpreting it as the specified shell dialect (overrides the shebang at the top of the script):
+- Check a shell script interpreting it as the specified [s]hell dialect (overrides the shebang at the top of the script):
 
 `shellcheck --shell {{sh|bash|dash|ksh}} {{path/to/script.sh}}`
 
-- Ignore one or more error types:
+- Ignor[e] one or more error types:
 
-`shellcheck --exclude {{SC1009,SC1073}} {{path/to/script.sh}}`
+`shellcheck --exclude {{SC1009,SC1073,...}} {{path/to/script.sh}}`
 
 - Also check any sourced shell scripts:
 
 `shellcheck --check-sourced {{path/to/script.sh}}`
 
-- Display output in the specified format (defaults to `tty`):
+- Display output in the specified [f]ormat (defaults to `tty`):
 
 `shellcheck --format {{tty|checkstyle|diff|gcc|json|json1|quiet}} {{path/to/script.sh}}`
 
-- Enable one or more optional checks:
+- Enable one or more [o]ptional checks:
 
-`shellcheck --enable={{add-default-case|avoid-nullary-conditions}}`
+`shellcheck --enable {{add-default-case,avoid-nullary-conditions,...}} {{path/to/script.sh}}`
 
 - List all available optional checks that are disabled by default:
 
 `shellcheck --list-optional`
+
+- Adjust the level of [S]everity to consider (defaults to `style`):
+
+`shellcheck --severity {{error|warning|info|style}} {{path/to/script.sh}}`