using the tar command

tar is useful if you want to stuff a bunch of files and directories into one file. Then you can scp that file to another machine, untar it, and you have a nice copy of your original files and dirs.

Use the c option to create a tar file:

$ tar cvf cs21.tar cs21 
cs21/
cs21/fortest.c
cs21/ch02/
cs21/ch02/a.out
cs21/ch02/coins.c
cs21/ch02/comm/
cs21/ch02/comm/file1
cs21/ch02/comm/file2
cs21/ch02/ops.c
cs21/ch03/
cs21/ch03/bug.c
cs21/ch03/p14.c
cs21/ch03/a.out
cs21/ch03/p9.c
cs21/ch03/randnum.c
cs21/ch03/list
cs21/ch03/p7.c
cs21/project.html

This creates (c) a tar file (f) called cs21.tar, which contains everything in my cs21 dir. The original cs21 dir is still there and untouched.

Don't use the verbose (v) option if you don't want to see all of the filenames go by.

Use the x option to extract the contents of a tar file:

$ tar xvf cs21.tar 
cs21/
cs21/fortest.c
cs21/ch02/
cs21/ch02/a.out
cs21/ch02/coins.c
cs21/ch02/comm/
cs21/ch02/comm/file1
cs21/ch02/comm/file2
cs21/ch02/ops.c
cs21/ch03/
cs21/ch03/bug.c
cs21/ch03/p14.c
cs21/ch03/a.out
cs21/ch03/p9.c
cs21/ch03/randnum.c
cs21/ch03/list
cs21/ch03/p7.c
cs21/project.html

This creates (or overwrites!) the cs21 directory and extracts all of the files and dirs from the tar file into the cs21 dir. The original cs21.tar file remains -- you can extract/untar as many times as you want.