bash-o-logist questions

bash-o-logist answers

• Shell script argument present or not
• Rename all files in directory from $filename_h to $filename_half?
• BASH: how to put variable inside regex?
• How do I delete a matching line and the previous one?
• Invoking a command line with spaces from a variable in a Bash script [duplicate]
• bash: debug option and functions
• How to Get a Substring Using Positive and Negative Indexes in Bash
• Return string until matched string in Ruby