Explain what the following statements do:

1. ls mydir > foo.txt
2. ls mydir > foo.txt 2>&1
3. cat file1 file2 > file3
4. cat file1 file2 >> file3

Write the Bash statements to:

1. Create a new file called banana-file-names.txt with the concatenated contents of every file in the current directory that starts with "banana"
2. Create a new file called banana-file-content.txt with the concatenated contents of every file in the current directory that contains the word "banana"

Write the Bash statements to:

1. Count the number of files ending in .java, in the current directory that have the string "pumpkin" in the file contents?
2. Do the same, including files in any sub-directory (recursively)
3. Replace every occurrence of "pumpkin" with "banana" in each of the files

Explain what each of the following Bash statements does and the overall result:

$ (date ; ps -ef | awk ‘{print $1}’ | sort | uniq | wc -l ) >> processes.log

Explain what the following Bash command does:

find . -type f -atime -7 > /tmp/recent_files

Explain what the following code does:

package Person;
sub new {
    my $self = {
        _firstName => undef,
        _lastName  => undef,
        _ssn       => undef,
        _address   => undef,
        _salary    => undef,
        _dept      => undef
    };
    bless $self, 'Person';
    return $self;
}

sub print {
    my ($self) = @_;
    printf( "Name:%s %s\n\n", $self->firstName, $self->lastName );
}

Describe two ways to concatenate strings in Perl. Contrast and compare.

Describe what the following Perl code does:

#!/usr/bin/perl
$numArgs = $#ARGV + 1;
print "$numArgs\n";
foreach $argnum (0 .. $#ARGV) {
print "$ARGV[$argnum]\n";
}

Write code to print the contents of the following array in Perl:

@fruit = ('banana', 'orange', 'apple');

In Perl, how would you allow functions to have private variables that retain their values from call to call?

What is a good way to fetch the contents of a web page in Perl, given a URL?

What is a common way of sending email from a Perl program?

Write a program to measure how long a context switch takes on the Unix operating system.