A telephone directory, called teledir. txt, maintains records in the form name: number where number is of the form nnn-nnn- for example; Chelsey: 480-727-1007
Devise a shell script that accepts one or two arguments that could be:

the name or number. If it exists in the directory, then the line should be displayed.
both. The entry is displayed if it exists and is added if it doesn’t exist in the file.
You can follow the steps below (not the only way):

Assign the pathname to the file teledir. txt to a variable, say, TELEDIR. For example, if it is in your home directory, you’ll need to assign $HOME/teledir. txt to the variable TELEDIR
Check that one or two arguments are supplied using $# and the case…esac construct.
If one or two arguments are supplied, do nothing
otherwise, Indicate that the usage must be in the form scriptname [name number], then exit
Using the $# and the case…esac construct,
If one argument is supplied,
If it starts with a digit, search it in the file. If it doesn’t exist, echo that "Number doesn’t exist"
If it starts with a letter (lower or uppercase), search it in the file. If it doesn’t exist, echo that "Name doesn’t exist"
If two arguments are supplied, set the search_pattern to be "name: number", and search it in the file.
If it is not found, echo "Adding entry", and append to the file/variable.
Otherwise, echo that "Entry exists"