Assignment

Your assignment, should you choose to accept it, is to complete a Perl script that reads through the following output, finds the CM2 gas-phase dipole moment (.616), and print it out. You can copy and paste the following output into a text file:

Charge Models 2 and 3 (CM2 and CM3) and Solvation Model SM5.42 GAMESSPLUS version 4.3 ------------------------------------------------ Gas-phase ------------------------------------------------ Center Atomic CM2 Lowdin Number Number Charge Charge ------------------------------------------------ 1 1 .139 .163 2 16 -.128 -.160 3 16 -.158 .041 4 6 .001 -.703 5 1 .050 .222 6 1 .048 .218 7 1 .048 .218 ------------------------------------------------ Gas-phase dipole moment (Debye) ------------------------------------------------ X Y Z Total CM2 -.553 -.271 .000 .616 Lowdin .288 .199 .000 .350 ------------------------------------------------ BREAKDOWN OF G_P AND G_CDS (KCAL/MOL) ------------------------------------------------ Center Atomic Atomic contribution Number Number G_P G_CDS ------------------------------------------------ 1 1 -.300 1.553 2 16 -.090 -3.324 3 16 -.282 -3.023 4 6 -.001 1.467 5 1 -.133 -.284 6 1 -.105 -.305 7 1 -.105 -.305 TOTAL -1.017 -4.221 ------------------------------------------------

Details

Your script should be robust enough that it will work with any similar output.

Your script might look something like:
#!/usr/bin/perl open(FILE1, ...something ); while (<FILE1>){ if ($_ =~ /some pattern match/){ print something } } close FILE1;

Tips

• @ARGV is the list of arguments passed to the script.
• while (<FILE>) will process FILE one line at a time until the end of file.
• $_ is the special variable that holds the current topic (current line in this case).
• The special variables $1, $2, $3 hold the matching sub-pattern from the most recent pattern match.
• In a regular expression, \s will match whitespace and \S will match non-whitespace. Placing a '+' after an item will match 1 or more of that item.

A solution

#!/usr/bin/perl open(FILE1,"<$ARGV[0]"); while (<FILE1>){ if ($_ =~ /CM2(\s+\S+){3}(\s+\S+)/){ print "The CM2 Diplole is: $2 \n" } } close FILE1;