One question about Unix

[sidlampard]

This is an assignment question, I know i should do it myself, but believe me i have just learned this subject and couldn't find the answer. Please if someone could give me the answer, i would be greatfull. And please if you could hurry because I have to submit on march 3 and only this question is left. Here is the question:

Reduce the number of key strokes to execute this command: tar -t-v-f/dev/fd0

[griswolf]

Hint: most unix utilities accept a compact form multiple flags where you only give a single dash. The tar utility is so old that it doesn't even always require dashes at all.

[wulaishiwo]

The shortest solution I can think of is

tar tvf/dev/fd0

[Potion]

The -t option lists the table of contents, and so the -v (verbose) option could be considered redundant. Just use:

tar tf /dev/fd0

[Potion]

Unrelated (except that it uses tar), here's a nice trick for copying trees while preserving file owner, permissions and date attributes. Every Linux/Unix hack should know this:

$ cd /source_dir
$ tar -cf - * | (cd /target_dir; tar xvf -)

Explanation.
In the source directory we create an archive of all the contents sending the stream to std-out. We then pipe the stream to to a grouped command, which first changes directory, and then extracts the archive from the std-in stream.