Sams Teach Yourself Shell Programming in 24 Hours, Second Edition

Hour 3

1:	What are invisible files? How can they be listed with ls?
A1:	Invisible files are files with names that start with the . character. You can list them by specifying the -a option to ls.
2:	Is there any difference in the output of the following commands? $ ls -a1 $ ls -1 -a $ ls -1a
A2:	No. Each of these commands will produce the same results.
3:	Which options should be specified to wc to count just the number of lines and characters in a file?
A3:	On Solaris, HPUX and BSD (including MacOS X), use the command $ wc -lm On Linux use the command $ wc -lc
4:	Given that hw1, hw2, ch1, and ch2 are files and book and homework are directories, which of the following commands generates an error message? $ cp hw1 ch2 homework $ cp hw1 homework hw2 book ...