Strange print behaviour in perl

[Mark McDonald_2]

Hi All,

We are developing a checking script written in perl, it runs some scripts on a host then emails the output as csv to allow it to be imported in to excel.

The report is started with:

open(MAILX,"|/usr/bin/mailx -s \"$type Handover report for $host\" $email");
print MAILX "$host: $uname\n\n $r/$c checks failed, details below:\n\n";

foreach(@$errors) {
print MAILX "\t$_\n\n";


Then it runs through thte output from each script, creating the csv details, see example below:

print MAILX "23,HW/ OS,OS (Red Hat),(Red Hat Linux specific item / TBD) t ," ;
if($results->[23]{result})
{ print MAILX "$results->[23]{result}"; }
print MAILX "," ;
if($results->[23]{error})
{ print MAILX "$results->[23]{error}"; }
print MAILX "\n"; <+++++++++++

print MAILX "24,HW/ OS,OS (SuSE),(SuSE Linux specific item / TBD) ," ;
if($results->[24]{result})
{ print MAILX "$results->[24]{result}"; }
print MAILX "," ;
if($results->[24]{error})
{ print MAILX "$results->[24]{error}"; }
print MAILX "\n";


The creates output like:
.
.
6,HW/ OS,General,OS internal disk mirroring configured properly ,FAIL,/dev/vg00/lvolu11 not mirrored.
.
.
23,HW/ OS,OS (Red Hat),(Red Hat Linux specific item / TBD) t ,N/A,NON-HPUX
24,HW/ OS,OS (SuSE),(SuSE Linux specific item / TBD) ,N/A,NON-HPUX
25,Backup,Backup,scheduled filesystem backup configured and working ,PASS,OK


However - Sometimes the newline marked with <+++++++ fails to show in the email. The new line is wholly dependent on the line ending TBD) t ," ;
If there are less than 3 spaces before the comma the newline fails to print. The t is in there for testing purposes. Any Ideas why?

We are having similar problems with other lines, too, some seem to require 4 spaces before the comma, others are happy with 2.

Anyone come across this before?

[James R. Ferguson]

Hi Mark:

This doesn't make sense. Have you set the 'stict' and 'warnings' pragma in your script? If not, at least for the purposes here do 'use warnings;'

Regards!

...JRF...

[Mark McDonald_2]

JRF - I agree it makes no sense at all. I did not write the script and I do not know perl. But I'm learning fast!!!!

I added "use warnings;" near the top and got an error:
Can't locate warnings.pm in @INC

So give me a few minutes with my good friend google....

[Mark McDonald_2]

ok - perl is version 5.005_03

[Mark McDonald_2]

It is using the "-w" on the shebang line...

[James R. Ferguson]

Hi (again) Mark:

> Can't locate warnings.pm in @INC

This would suggest that your version of Perl is very old. To see your version, do:

# perl -v

In lieu of the 'warnings' pragma, you can use the older:

#!/usr/bin/perl -w

...at the interpreter line.

Regards!

...JRF...

[James R. Ferguson]

HI (again) Mark:

My guess is that your data-dependent behavior may involve things like carriage-return (\r) or backspace (\010) characters.

For example:

# perl -e 'print STDERR "hi","\r";print "?\n"'
?i

You might try adding an automatic linefeed to print statements with the '-l' switch. Hence on your shebang (interpreter line):

#!/usr/bin/perl -wl

Regards!

...JRF...

[Mark McDonald_2]

OK - I will give that a try - however due to the way is is printing the data, I will need some way of supressing it for some of the print statements.

Does "printf" work in perl?

[Hein van den Heuvel]

1) Yes, printf works find in perl,

2) 5.005_03

That's wicked old.
Not having looked for a solid timeline,
I would guess over 10 years.
5.6 was normal 5 years back, 5.8 pretty standard. 5.10 desirable most platforms.
Just a gutfeel.

Hein.

[James R. Ferguson]

HI (again) Mark:

> Does "printf" work in perl?

Yes, and that would be the most appropriate way to handle your needs. The 'printf' function works just like you would expect.

Regards!

...JRF...

[Mark McDonald_2]

Thanks all.

I will approach the boss regarding upgrading the perl version, and have a play with the "-l" and printf.

[Mark McDonald_2]

Just been informed there is a perl 5.8 on the box, so will be playing with that too!!!

[Mark McDonald_2]

OK, what is this line doing?

if($results->[9]{result}) { print MAILX "$results->[9]{result}";

I guess its - if array result position 9 contains something, then print it....

Can some one help me understand this bit?

[Mark McDonald_2]

Thanks guys - using 5.8 now, and its doing what it is supposed to with print and \n where needed.

Script is a lot tidier now and I am adding comments as I work out what each bit does. Another few days of this and Perl scripting will be going on my CV!!!!