BASH Scripting Problems

2. Calculate letter frequencies a. If no file provided read from stdin b. If one or more file is provided calculate frequencies per file c. If one or more file is provided write an error for any argument that isn't a valid regular file d. Optional flags i. flags to calculate frequencies both case-sensitive and non-case sensitive ii. print cumulative frequency 2. Calculate letter frequencies a. If no file provided read from stdin b. If one or more file is provided calculate frequencies per file c. If one or more file is provided write an error for any argument that isn't a valid regular file d. Optional flags i. flags to calculate frequencies both case-sensitive and non-case sensitive ii. print cumulative frequency