Title: reading/writing to a ascii file
Ok guys here is the pickle I'm in now =-) I need to read from a ASCII file and only modify the lines that match a variable.
I do not want to read the entire file into memory and write the entire file out each time I need to make a change.
Here is what
ok let's say I have a 500,000 line file... What I want is for the script
to
read the file in line by line and only change the 1 line I am looking for.
ex: line 550 contains the line I am looking for I want to change that line
and not have to re-create the file.
You could do this:
perl -i -p
Ryan, it's easier than you think:
open(IN, $inputfile) or die can't open $inputfile: $!;
open(OUT,$outputfile) or die can't open $outputfile: $!;
while (IN){
s/$string/$replacement/g;
print OUT $_;
}
close IN;
close OUT;
rename($outputfile, $inputfile) or die can't rename... $!;
Title: RE: reading/writing to a ascii file
That is still opening and reading the entire file and then creating an entire new file... I may run into instances where the file will be opened and modified many times.
-Original Message-
From: Thomas, Mark - BLS CTR [mailto:[EMAIL
That is still opening and reading the entire file
and then creating an entire new file...
No, it's not. It reads only one line at a time into memory. This is quite
different from your version which read the entire file into memory.
Are you looking to avoid *both* reading the file into memory
Ok guys here is the pickle I'm in now =-) I need to read from
a ASCII file and only modify the lines that match a variable.
I do not want to read the entire file into memory and write
the entire file out each time I need to make a change.
Here is what I am doing that reads the entire file
