Add draft post generate-password-cli

_posts/2024-11-09-generate-password-cli.md

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+---
+layout: post
+title: Generate password with command line in Linux or macOS
+date: 2024-11-09 16:16:00-0700
+description: If you usually work with command line in Linux or macOS, you can use it to generate password without installing any additional application.
+tags: cli password-generating command-line linux macos
+categories: utilities
+giscus_comments: true
+related_posts: false
+toc:
+  beginning: true
+---
+
+Most websites or application require a strong password that contains a mix of letters, numbers and special characters. And to make it more secure, it should be unique and randomly generated for each account.
+If you are using Linux or macOS and usually work with command line, you can use it to generate without installing any additional application.
+
+### Using /dev/urandom or /dev/random
+
+This is my favorite way to generate password because `/dev/urandom` and `/dev/random` are available in most Unix-like operating systems.
+
+```sh
+< /dev/urandom tr -dc '[:graph:]' | head -c32; echo
+```
+
+This command will create a random password with printable character, length is 32.
+
+In case that alphabet & numeric character, use `alnum` instead of `graph`.
+
+For more information, see `tr` [manpage](https://linuxcommand.org/lc3_man_pages/tr1.html)
+
+With macOS, an error occur when run above command because of UTF-8. Just add LC_ALL=C as below:
+
+```sh
+< /dev/urandom LC_ALL=C tr -dc '[:graph:]' | head -c32; echo
+```
+
+#### Random
+
+/dev/random takes the random values from the entropy pool. If the entropy pool is empty, it will be blocked reading.
+
+#### URandom (Unlimited Random)
+
+/dev/urandom is similar to /dev/random but in case that entropy pool is empty, it generate value using hashing argorithm such as: SHA, MD5, ...
+
+#### In term of security
+
+Because of high-quality randomness of /dev/random, it's suitable for a password or a task focus on security.
+
+### Using openssl
+
+```sh
+openssl rand -base64 32
+```
+
+This command can only generate a base64 string password.
+
+### Using date and hashing
+
+```sh
+date | md5
+```
+
+It similar to openssl command, but it's not really random like openssl or /dev/urandom.
+
+### Using gpg
+
+```sh
+gpg --gen-random 1 32
+```