diff --git a/computing_shell_scripts.md b/computing_shell_scripts.md
index 6336605..0b36d41 100644
--- a/computing_shell_scripts.md
+++ b/computing_shell_scripts.md
@@ -11,4 +11,16 @@ There are several flavours of Linux shells. Bash is one of the most common.
 ## Bourne-Again SHell (BASH)
  - [Bash scripting cheatsheet](https://devhints.io/bash)
  - [30 Bash script examples](https://linuxhint.com/30_bash_script_examples/)
- - [Bash Scripting Tutorial for beginners](https://linuxconfig.org/bash-scripting-tutorial-for-beginners)
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+ - [Bash Scripting Tutorial for beginners](https://linuxconfig.org/bash-scripting-tutorial-for-beginners)
+
+## variables in a bash script
+$0 - The name of the Bash script.
+$1 - $9 - The first 9 arguments to the Bash script. (As mentioned above.)
+$# - How many arguments were passed to the Bash script.
+$ - All the arguments supplied to the Bash script.
+$ - The exit status of the most recently run process.
+$$ - The process ID of the current script.
+$USER - The username of the user running the script.
+$HOSTNAME - The hostname of the machine the script is running on.
+$SECONDS - The number of seconds since the script was started.
+$RANDOM - Returns a different random number each time is it referred to.
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