Finding a Letter at Last line

mantra2006 has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks
We will be downloading files from server...we have to check for end of
file starts with "T" if this is there then we treat
this as complete file and do further processing otherwise
its not a complete file and we will
wait for the file. for eg. if the file has the following

0000000508120060901                                   
3TEST C TEST          0000000508220060901                             
+     TEST123              0000000005120060901                        
+           
300055566             0000000509720060901                             
+            1ABC30620060901      000DDDD      24702R101 B000000272730
+000000000500000000 OTC                                               
+          C                                                          
+ 2TC12345              00000000188     JEMPRUTEST           000000089
+89     TONY C TEST          00000008990     TEST123              0000
+0000090      
200055566             00000009016                                     
+            TJHY30600000000009
[download]

As above the last line started with "T" we can assume its complete file..

Thanks & Regards
Sridhar

Comment on Finding a Letter at Last line Download Code

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Re: Finding a Letter at Last line by davidrw (Prior) on Nov 08, 2006 at 16:17 UTC
TWTOWTDI :) `perl -lne '$s=$_; END{ print "OK" if $s=~/^T/ }' /tmp/foo` [download] Though you might want exit codes instead, depending on what's calling this `perl -ne '$s=$_; END{ exit($s=~/^T/ ? 0 : 1) }' /tmp/foo` [download] Or, using File::Tie: `perl -MTie::File -e 'tie @f, "Tie::File", shift; exit 1 unless $f[-1] +=~ /^T/' /tmp/foo` [download] Or, using File::ReadBackwards (untested): `perl -MFile::ReadBackwards -e 'exit 1 unless File::ReadBackwards->new( +shift)->readline =~ /^T/' /tmp/foo` [download]	[reply] [d/l] [select]
Re: Finding a Letter at Last line by smokemachine (Hermit) on Nov 08, 2006 at 15:58 UTC
could be this? `perl -e 'open FILE, "<file"; $_ = join "", <FILE>; print "Download fin +ished" if /^t[^\n]*\Z/msi'` [download]	[reply] [d/l]
Re^2: Finding a Letter at Last line by mantra2006 (Hermit) on Nov 08, 2006 at 16:37 UTC
Hey smokemachine Thanks for the reply..it worked..just a small doubt how can i replace "<file" with variable filenames?? Thanks & Regards Sridhar	[reply]
Re^3: Finding a Letter at Last line by smokemachine (Hermit) on Nov 08, 2006 at 16:42 UTC
yes... you can use `"<$filename"`	[reply] [d/l]
Re^4: Finding a Letter at Last line by mantra2006 (Hermit) on Nov 08, 2006 at 16:49 UTC
Re^5: Finding a Letter at Last line by smokemachine (Hermit) on Nov 08, 2006 at 16:58 UTC
Re^5: Finding a Letter at Last line by Anonymous Monk on Nov 08, 2006 at 17:02 UTC
Some notes below your chosen depth have not been shown here
Re: Finding a Letter at Last line by davido (Cardinal) on Nov 08, 2006 at 17:07 UTC
You might like using File::ReadBackwards, since it efficiently begins reading chunks from the end of the file, without wasting time starting at the beginning and paging your way through the file until you find the end. `my $bw = File::ReadBackwards->new( 'your.filename' ) or die "can't read 'your.filename'\n$!"; if( defined( my $last_line = $bw->readline ) and $last_line =~ m/^T/ ) { # do your processing here... }` [download] If it turns out that it's ok to have leading space before the 'T', you would have to modify the regexp to look like this: `m/^\s*T/` Another convenient way (though less efficient) is Tie::File, where your file becomes an array. The last line could be accessed as `$file[-1]`. Dave	[reply] [d/l] [select]
Re: Finding a Letter at Last line by johngg (Canon) on Nov 08, 2006 at 16:09 UTC
But the last line doesn't start with a "T". Do you mean the last field of the last line? Cheers, JohnGG	[reply]
Re: Finding a Letter at Last line by fenLisesi (Priest) on Nov 08, 2006 at 16:08 UTC
How big can these files get? (btw, the last line doesn't seem to start with T there)	[reply]
Re: Finding a Letter at Last line by Anonymous Monk on Nov 08, 2006 at 15:58 UTC
Assuming you have the entire content of the file in a string called $var (if you have them line by line in an array, just see whether the first character of the last element is a T), you could do: `$text =~ /(?:^\|\n)T[^\n]*$/` [download]	[reply] [d/l]