test: todo - comments
test: todo - logging (levels,stdout,stderr,logfile...)
test: todo - nonewline
test: todo - concatenation
test: todo - print array
test: todo - print (formatted?) variables
test: todo - find caracter position and print
test: todo - split string print first array item
test: todo - if ... else
test: todo - functions and calling functions
test: todo - regex
test: todo - replacement and string edit
test: todo - external OS commands
test: todo - edit file
test: todo - edit file using other modes
test: todo - fs operations
test: todo - compress existing file
test: todo - input data
test: todo - CLI arguments
test: todo - switch/case statement?
test: todo - tk
test: todo - debug
test: todo - time conversion
test: todo - associative arrays or key/value pairs
test: todo - JSON & XML
test: todo - gethostbyname / addr
test: todo - sockets
test: todo - threads
test: todo - html string.Template systems (and CGI)
test: todo - sleep

we are not limited to this list, depending on the language it can change and be extended