Hack 21. Change the Case Using tr Command

Convert a file to all upper-case using tr command as shown below.

$ cat employee.txt

100 Jason Smith
200 John Doe
300 Sanjay Gupta
400 Ashok Sharma

$ tr a-z A-Z < employee.txt

100 JASON SMITH
200 JOHN DOE
300 SANJAY GUPTA
400 ASHOK SHARMA