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Workshop

Quiz

1:

To have data generated by your program display a page at a time, use

  1. perl myprog.pl | more

  2. open(M, "| more") || die; print M "data...data...data....\n";

  3. open(M, ">more") || die; print M "data..data...data...\n";

2:

Which value of $foo is used in this statement: $r=`dir $foo`?

  1. The shell's value for $foo.

  2. Perl's value of $foo is substituted, and then the dir is run.

3:

Which of the following tasks changes depending on what system you have?

  1. Finding the amount of free disk space

  2. Getting a directory listing

  3. Deleting a directory

Answers

A1:

Either a or b. In the case of a, all output of myprog.pl is fed to more. In the case of b, any data written to the M file descriptor is fed to more for paging.

A2:

b. To protect $foo from Perl's expansion, you use qx`dir $foo`.

A3:

a only. Choice b can be done with glob, <*> or opendir and readdir, and c is done with rmdir.

Activities

  • Use the statistics functions in Hour 8, "Functions," to display even more statistics about the sizes of files in Listing 11.1.

  • If you have a Unix system, add your particular flavor of Unix to the freespace() function. Use the Linux example as a starting point.

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