Instead of printing the file into one line, the output is a bunch of new lines. What am I ding wrong in the file path of this perl script?
Script:
my $app = $ARGV[0];
my $day=`date -v-1d '+%d'`;
my $month=`date -v-1d '+%b'`;
my $yr=`date -v-1d '+%Y'`;
my $file = "/path/to/file/$app/$yr/$month/treshold-$day .log";
print $file;
Result:
$ perl test.pl inter
/path/to/file/inter/2013
/Dec
/treshold-13
Output should be: /path/to/file/inter/2013/Dec/treshold-13.log
date(1) write an end-of-line at the end of the output. Use chomp to throw it away.
Related
How to read the text file using perl command line arguments and print the third column using perl?
I'm struck with taking input from the command line and printing the required column. Help me to choose the right way to reach the expected output.
Code which I wrote to take command line input:(map.pl)
use strict;
use warnings 'all';
use Getopt::Long 'GetOptions';
my #files=GetOptions(
'p_file=s' => \my $p_file,
);
print $p_file ? "p_file = $p_file\n" : "p_file\n";
Output I got for above code:
perl map.pl -p_file cat.txt
p_file = cat.txt
cat.txt:(Input file)
ADG:YUF:TGH
UIY:POG:YTH
GHJUR:"HJKL:GHKIO
Expected output:
TGH
YTH
GHKIO
Perl can automatically read files whose names are provided as command line arguments. The command below should produce your expected output
perl -F: -le 'print $F[2]' cat.txt
-F: turns on autosplit mode, sets the field separator to : and loops over lines of input files. -l handles line endings during input and output. The code after e flag ('print $F[2]' prints 3rd field) is executed for each line of file. Find out more by reading perldoc perlrun.
You'd need to read the file and split the lines to get the columns, and print the required column. Here's a demo code snippet, using the perl -s switch to parse command line arguments. Run like this ./map.pl -p_file=cat.txt
#!/usr/bin/perl -s
use strict;
use warnings;
use vars qw[$p_file];
die("You need to pass a filename as argument") unless(defined($p_file));
die("Filename ($p_file) does not exists") unless(-f $p_file);
print "Proceeding to read file : $p_file\n\n";
open(my $fh,'<',$p_file) or die($!);
while(chomp(my $line = <$fh>)) {
next unless(defined($line) && $line);
my #cols = split(/:/,$line);
print $cols[-1],"\n";
}
close($fh);
I'm new in Perl, so it's maybe a very basic case that i still can't understand.
Case:
Program tell user to types the file name.
User types the file name (1 or more files).
Program read the content of file input.
If it's single file input, then it just prints the entire content of it.
if it's multi files input, then it combines the contents of each file in a sequence.
And then print result to a temporary new file, which located in the same directory with the program.pl .
file1.txt:
head
a
b
end
file2.txt:
head
c
d
e
f
end
SINGLE INPUT program ioSingle.pl:
#!/usr/bin/perl
print "File name: ";
$userinput = <STDIN>; chomp ($userinput);
#read content from input file
open ("FILEINPUT", $userinput) or die ("can't open file");
#PRINT CONTENT selama ada di file tsb
while (<FILEINPUT>) {
print ; }
close FILEINPUT;
SINGLE RESULT in cmd:
>perl ioSingle.pl
File name: file1.txt
head
a
b
end
I found tutorial code that combine content from multifiles input but cannot adapt the while argument to code above:
while ($userinput = <>) {
print ($userinput);
}
I was stucked at making it work for multifiles input,
How am i suppose to reformat the code so my program could give result like this?
EXPECTED MULTIFILES RESULT in cmd:
>perl ioMulti.pl
File name: file1.txt file2.txt
head
a
b
end
head
c
d
e
f
end
i appreciate your response :)
A good way to start working on a problem like this, is to break it down into smaller sections.
Your problem seems to break down to this:
get a list of filenames
for each file in the list
display the file contents
So think about writing subroutines that do each of these tasks. You already have something like a subroutine to display the contents of the file.
sub display_file_contents {
# filename is the first (and only argument) to the sub
my $filename = shift;
# Use lexical filehandl and three-arg open
open my $filehandle, '<', $filename or die $!;
# Shorter version of your code
print while <$filehandle>;
}
The next task is to get our list of files. You already have some of that too.
sub get_list_of_files {
print 'File name(s): ';
my $files = <STDIN>;
chomp $files;
# We might have more than one filename. Need to split input.
# Assume filenames are separated by whitespace
# (Might need to revisit that assumption - filenames can contain spaces!)
my #filenames = split /\s+/, $files;
return #filenames;
}
We can then put all of that together in the main program.
#!/usr/bin/perl
use strict;
use warnings;
my #list_of_files = get_list_of_files();
foreach my $file (#list_of_files) {
display_file_contents($file);
}
By breaking the task down into smaller tasks, each one becomes easier to deal with. And you don't need to carry the complexity of the whole program in you head at one time.
p.s. But like JRFerguson says, taking the list of files as command line parameters would make this far simpler.
The easy way is to use the diamond operator <> to open and read the files specified on the command line. This would achieve your objective:
while (<>) {
chomp;
print "$_\n";
}
Thus: ioSingle.pl file1.txt file2.txt
If this is the sole objective, you can reduce this to a command line script using the -p or -n switch like:
perl -pe '1' file1.txt file2.txt
perl -ne 'print' file1.txt file2.txt
These switches create implicit loops around the -e commands. The -p switch prints $_ after every loop as if you had written:
LINE:
while (<>) {
# your code...
} continue {
print;
}
Using -n creates:
LINE:
while (<>) {
# your code...
}
Thus, -p adds an implicit print statement.
I have a huge file which consists of similar lines below , with different clocks:
cmd -quiet [get_ports p1] ref_clocks "cudtclk_sp cudtclk"
cmd -quiet [get_ports p2] clock "cu2xdtclk_sp cu2xdtclk"
And I need to replace cudtclk with some other name like cdtclk whenever I have ref_clocks in my file, globally.
I have written following code but it doesn't seem to be working.
#!/usr/bin/perl
use strict;
use warnings;
sub clock_change
{ # Get the subroutine's argument.
my $arg = shift;
# Hash of stuff we want to replace.
my %replace = (
"cudtclk" => "cdtclk",
);
# See if there's a replacement for the given text.
my $text = $replace{$arg};
if(defined($text)) {
return $text;
}
return $arg;
}
open PAR, "<file name>";
while(<PAR>) {
$_ =~ s/\S+\s\S+\s\S+\s\S+\sref_clocks\s+(\S+\s+\S+)/clock_change($1)/eig;
print $_; ##print it to some file later.
}
"And I need to replace cudtclk with some other name like cdtclk"
perl -pe 's/\bcudtclk\b/cdtclk/' thefile > newfile
"whenever I have ref_clocks"
perl -pe 's/\bcudtclk\b/cdtclk/ if /\bref_clocks\b/' thefile > newfile
Alternatively:
# saves original file as file.bak
perl -i.bak -pe 's/\bcudtclk\b/cdtclk/ if /\bref_clocks\b/' file
Tighten to suit your data, as necessary.
Although the substitution seems like unnecessarily complex, you can fix it with something similar to:
$_ =~ s/(ref_clocks\s+")([^_]+)_sp(\s+)\2/
$1.clock_change($2)."_sp$3".clock_change($2)/eig;
My test file has "n" number of lines and between each line there is a ^M, which in turn makes it one big string. The code I am working with opens said file and should parse out a header and then the subsequent rows, then searches for the Directory Path and File name. But because the file just ends up as a big string it doesn't work correctly
#!/usr/bin/perl
#use strict;
#use warnings;
open (DATA, "<file.txt") or die ("Unable to open file");
my $search_string = "Directory Path";
my $column_search = "Filename";
my $header = <DATA>;
my #header_titles = split /\t/, $header;
my $extract_col = 0;
my $col_search = 0;
for my $header_line (#header_titles) {
last if $header_line =~ m/$search_string/;
$extract_col++;
}
for my $header_line (#header_titles) {
last if $header_line =~m/$column_search/;
$col_search++;
}
print "Extracting column $extract_col $search_string\n";
while ( my $row = <DATA> ) {
last unless $row =~ /\S/;
chomp $row;
my #cells = split /\t/, $row;
$cells[74]=~s/:/\//g;
$cells[$extract_col]= $cells[74] . $cells[$col_search];
print "$cells[$extract_col] \n";
}
When i open the test file in VI i have used
:%s/^M/\r/g
and that removes the ^M's but how do i do it inside this perl program? When i tried a test program and inserted that s\^M/\r/g and had it write to a different file it came up as a lot of Chinese characters.
If mac2unix isn't working for you, you can write your own mac2unix as a Perl one-liner:
perl -pi -e 'tr/\r/\n/' file.txt
That will likely fail if the size of the file is larger than virtual memory though, as it reads the whole file into memory.
For completeness, let's also have a dos2unix:
perl -pi -e 'tr/\r//d' file.txt
and a unix2dos:
perl -pi -e 's/\n/\r\n/g' file.txt
Before you start reading the file, set $/ to "\r". This is set to the linefeed character by default, which is fine for UNIX-style line endings, and almost OK for DOS-style line endings, but useless for the old Mac-style line endings you are seeing. You can also try mac2unix on your input file if you have it installed.
For more, look for "INPUT_RECORD_SEPARATOR" in the perlvar manpage.
Did this file originate on a windows system? If so, try running the dos2unix command on the file before reading it. You can do this before invoking the perl script or inside the script before you read it.
You might want to set $\ (input record separator) to ^M in the beginning of your script, such as:
$\ = "^M";
perl -MExtUtils::Command -e dos2unix file
I'm writing a Perl script to run an external program on every file in a directory. This program converts files from one format to another. Here's the deal...
When I run the program from the command line, everything works as it should:
computer.name % /path/program /inpath/input.in /outpath/output.out
converting: /inpath/input.in to /outpath/output.out
computer.name %
Here's the code I wrote to convert all files in a directory (listed in "file_list.txt"):
#!/usr/bin/perl -w
use warnings;
use diagnostics;
use FileHandle;
use File::Copy;
# Set simulation parameters and directories
#test_dates = ("20110414");
$listfile = "file_list.txt";
$execname = "/path/program";
foreach $date (#test_dates)
{
# Set/make directories
$obs_file_dir = "inpath";
$pred_file_dir = "outpath";
mkdir "$pred_file_dir", 0755 unless -d "$pred_file_dir";
# Read input file names to array
$obs_file_list = $obs_file_dir . $listfile;
open(DIR, $obs_file_list) or die "Could not open file!";
#obs_files = <DIR>;
close(DIR);
# Convert and save files
foreach $file (#obs_files)
{
$file =~ s/(\*)//g;
$infile = $obs_file_dir . $file;
$outfile = $pred_file_dir . $file;
$outfile =~ s/in/out/g;
print $infile . "\n";
#arg_list = ($execname, $infile, $outfile);
system(#arg_list);
}
}
The output shows me the following error for every file in the list:
computer.name % perl_script_name.pl
/inpath/input.in
converting: /inpath/input.in to /outpath/output.out
unable to find /inpath/input.in
stat status=-1
error while processing the product
I verified every file is in the proper place and have no idea why I am getting this error. Why can't the files be found? When I manually pass the arguments using the command line, no problem. When I pass the arguments through a variable via a system call, they can't be found even though the path and file names are correct.
Your advice is greatly appreciated!
Your list of files (#obs_files) comes from reading in a file via #obs_files = <DIR>;
When you do that, each element of array will be a line from a file (e.g. directory listing), with the line being terminated by a newline character.
Before using it, you need to remove the newline character via chomp($file).
Please note that s/(\*)//g; does NOT remove that trailing newline!