UNIX “cat” command doubts!! I’n new to UNIX so please bear with me. I wanted to know what does the cat file1.txt << file2.txt command do? it doesn’t give an error, just goes accepts the keyboard as stdinput, and on ctrl+d, contents of file1 nor file2 changes. Also one more thing in the terminal window itself, the keyboard as the stdinput, when pressing Esc twice it prints all the hidden files(starts with a period), or atleast thats what I think. What does it do.