or DIE adding line number to error

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: or DIE adding line number to error by sgifford (Prior) on Mar 10, 2005 at 03:09 UTC
Just put a newline at the end of the string in `die`: `open(LOG, "< $file") or die "Sorry could not open $file\n";` [download]	[reply] [d/l] [select]
Re: or DIE adding line number to error by Thilosophy (Curate) on Mar 10, 2005 at 03:11 UTC
`die` adds a line number only if the message string does not end in "\n". So if you want to suppress the line number, you can do `open(LOG, "< $file") or die "Sorry could not open $file\n";` [download] I was thinking doing an if/else and exit I'd say stick with `die`. `exit` cannot be trapped later on (in case you decide the error can be handled somehow), and if you do not trap the `die` it will `exit` anyway.	[reply] [d/l] [select]
Re: or DIE adding line number to error by Zaxo (Archbishop) on Mar 10, 2005 at 03:11 UTC
Add a "\n" to the end of your message. That will suppress file and line-number diagnostics. `$ perl -e'die "Willingly"' Willingly at -e line 1 $ perl -e'die "Willingly\n"' Willingly $` [download] After Compline, Zaxo	[reply] [d/l]
Re: or DIE adding line number to error by Tanktalus (Canon) on Mar 10, 2005 at 02:58 UTC
`open(LOG, "< $file") or do { print STDERR "Sorry, could not open $file: $!\n"; exit (1); }` [download] or `unless (open(LOG, "< $file")) { print STDERR "Sorry, could not open $file: $!\n"; exit (1); }` [download]	[reply] [d/l] [select]
Re^2: or DIE adding line number to error by jhourcle (Prior) on Mar 10, 2005 at 03:09 UTC
even easier: `open(LOG, "< $file") or die "Sorry could not open $file\n";` From die: If the value of EXPR does not end in a newline, the current script line number and input line number (if any) are also printed, and a newline is supplied. Note that the "input line number" (also known as "chunk") is subject to whatever notion of "line" happens to be currently in effect, and is also available as the special variable `$.'. See the section on "$/" in the perlvar manpage and the section on "$." in the perlvar manpage.	[reply] [d/l]
Re: or DIE adding line number to error by merlyn (Sage) on Mar 10, 2005 at 15:42 UTC
In the future, when you're curious about what a function is doing, you can go right to the source. In this case, `perldoc -tf die` says: `If the last element of LIST does not end in a newline, the current script line number and input line number (if any) +are also printed, and a newline is supplied. Note that the "in +put line number" (also known as "chunk") is subject to whateve +r notion of "line" happens to be currently in effect, and is + also available as the special variable $.. See "$/" in perlvar +and "$." in perlvar.` [download] I think that says pretty clearly that the behavior is expected, and how to alter the behavior. -- Randal L. Schwartz, Perl hacker Be sure to read my standard disclaimer if this is a reply.	[reply] [d/l]
Re: or DIE adding line number to error by baztastic (Scribe) on Mar 10, 2005 at 03:14 UTC
You could use unless and exit. And if you want to see why it fails you can add $! `unless(open(LOG, "< $file")){ print "Sorry could not open $file - $!","\n"; exit; }` [download] -baztastic	[reply] [d/l]
Re^2: or DIE adding line number to error by thor (Priest) on Mar 10, 2005 at 05:38 UTC
Why `print "Sorry could not open $file - $!","\n";` and not `print "Sorry could not open $file - $!\n";`? I know that they're equivalent, but you don't have to put the newline in its own string... thor `Feel the white light, the light within Be your own disciple, fan the sparks of will For all of us waiting, your kingdom will come`	[reply] [d/l] [select]
Re^3: or DIE adding line number to error by baztastic (Scribe) on Mar 10, 2005 at 21:35 UTC
To be honest I don't know. I was incredibly distracted when I wrote the response. When I originally started to reply no one else had replied yet, I probably should have looked it over better before submitting it. -baztastic	[reply]