perl import data
# Basic syntax: # For reading: open(my $in, "<", "infile.txt") or die "Can't open infile.txt: $!"; # For writing (overwrites file if it exists): open(my $out, ">", "output.txt") or die "Can't open output.txt: $!"; # For writing (appends to end of file if it exists): open(my $log, ">>", "my.log") or die "Can't open my.log: $!"; # Where: # The first argument to open creates a named filehandle that can be # referred to later # The second argument determines how the file will be opened # The third argument is the file name (use $ARGV[#] if reading from the CLI) # The or die "" portion is what to print if there is an error opening the file # Note, be sure to close the filehandle after you're done operating on the file: close $in; # You can read from an open filehandle using the "<>" operator. In # scalar context it reads a single line from the filehandle, and in list # context it reads the whole file in, assigning each line to an element # of the list: my $line = <$in>; my @lines = <$in>; # You can iterate through the lines in a file one at a time with a while loop: while (my $line = <$in>) { print "Found apples\n" if $line =~ m/apples/; } # You can write to an open filehandle using the standard "print" function: print $out @lines; print $log $msg, "\n";
Source: learnxinyminutes.com