Reading and writing text files

…Eventually, you'll probably want to work with files.…If you want to work with content of binary files, you're on your own for that.…That's a territory better served by C or something a bit lower level.…But working with text files in Bash is pretty easy.…The greater than and less than symbols are key here.…For example, if I write, echo, "Some text" > file.txt,…bash writes the string, Some text, to a file called file.txt.…Creating it if it doesn't and overwriting anything that's already in it.…You're probably familiar with this from working with output redirection.…

You can use the greater than operator by itself to…zero out a file, getting rid of anything that's inside it.…But let's put something back in there.…If you want to add onto the end of a file…rather than replace it, you can use two greater than symbols.…So what about reading files?…Well, for that, you can use a while loop, along with a read command.…This syntax reads the file, file.txt, into the variable f line by line.…To see this in action, I'll add an…