I'm wondering why my string is still empty when just hitting enter after this code:
$file = <>;
if ($file eq "") {
$file = "test.txt";
}
print "$file";
If I type in anything, it is presented by the print command, but when I just hit enter, nothing is printed out. What I want is for perl to understand when the user inputs nothing and automatically edit the string to, in this case, test.txt. What am I doing wrong?
Thanks!
Because "enter" is not equal to nothing -- it's equal to \n.
$file = <>;
if ($file eq "") {
$file = "test.txt";
}
print length($file);
Run this, hit ENTER, and watch as you get -- 1!
Try:
$file = <>;
if ($file eq "\n") {
$file = "test.txt";
}
print "$file";
Bear in mind that \n isn't portable across systems. What you really want is something like:
$file = <>;
if ($file =~ /^\s*$/) {
$file = "test.txt";
}
print $file;
to match on whitespace.
To get the result you want you have to chomp your line.
use strict;
use warnings;
chomp(my $file = <>); #remove newline. $file will have empty string if only a newline was entered.
if ($file eq "") {
$file = "test.txt";
}
print "$file\n";
Related
In my below program, I was trying to search a string from no of files In a folder but output Is printing in continuous manner rather than stopping after required search. Can some one pls help to point out the error ?
i.e. I am trying to Search the string "VoLTE SIPTX: [SIPTX-SIP] ==> REGISTER" from #files but I am not getting the desired output but I am getting repetitive output of my strings.
# #!/usr/bin/perl
# use strict;
use warnings;
&IMS_Compare_Message();
sub IMS_Compare_Message
{
print "Entering the value i.e. the IMS Message to compare with";
my $value = '';
my $choice = '';
my $loop = '';
print "\nThe script path & name is $0\n";
print "\nPlease enter desired number to select any of the following
(1) Start Comparing REGISTER message !!
(2) Start Comparing SUBSCRIBE message
(3) Start Comparing INVITE message \n";
$value = <STDIN>;
if ($value == 1 )
{
print "\n Start Comparing REGISTER message\n\n";
$IMS_Message = "VoLTE SIPTX: [SIPTX-SIP] ==> REGISTER";
#chomp ($IMS_Message);
}
elsif ($value == 2)
{
print "\n SUBSCRIBE message Flow\n\n";
}
elsif ($value == 3)
{
print "\n INVITE message Flow\n\n";
}
else
{
print "\nThe input is not valid!\n";
print "\nDo you want to continue selecting a Automation Mode again (Y or N)?\n";
$choice = <STDIN>;
if( $choice =~ /[Yy]/) {
test_loop();
} else {
exit;
}
}
my $kw = "$IMS_Message";
my #files = grep {-f} (<*main_log>);
foreach my $file (#files)
{
open(my $fh, '<', $file) or die $!;
my #content = <$fh>;
close($fh);
my $l = 0;
$search = chomp ($kw);
#my $search = quotemeta($kw);
foreach (#content)
{ # go through every line for this keyword
$l++;
if (/$search/)
{
printf 'Found keyword %s in file %s, line %d:%s'.$/, $kw, $file, $l, $_
}
}
}
}
After Modificaiton
# #!/usr/bin/perl
use strict;
use warnings;
print "Entering the value i.e. the IMS Message to compare with";
my $value = '';
my $choice = '';
my $loop = '';
my $IMS_Message = '';
my $search = '';
my $kw = '';
print "\nThe script path & name is $0\n";
print "\nPlease enter desired number to select any of the following
(1) Start Comparing REGISTER message !!
(2) Start Comparing SUBSCRIBE message
(3) Start Comparing INVITE message \n";
$value = <STDIN>;
if ($value == 1 )
{
print "\n Start Comparing REGISTER message\n\n";
$IMS_Message = "VoLTE SIPTX: [SIPTX-SIP] ==> REGISTER";
#chomp ($IMS_Message);
}
elsif ($value == 2)
{
print "\n SUBSCRIBE message Flow\n\n";
}
elsif ($value == 3)
{
print "\n INVITE message Flow\n\n";
}
else
{
print "\nThe input is not valid!\n";
print "\nDo you want to continue selecting a Automation Mode again (Y or N)?\n";
$choice = <STDIN>;
if( $choice eq /[Yy]/) {
test_loop();
} else {
exit;
}
$kw = $IMS_Message;
$search = qr/\Q$kw/;
for my $file ( grep { -f } glob '*main_log' ) {
open my $fh, '<', $file or die qq{Unable to open "$file" for input: $!};
while ( <$fh> ) {
if ( /$search/ ) {
printf "Found keyword %s in file %s, line %d: %s\n", $kw, $file, $., $_;
last;
}
}
}
}
Here are some observations on your code
Your approach to debugging appears to be to try things at random to see if they work. It would be far more fruitful to add diagnostic print statements so that you can compare variables' actual values with what you expect
Error and warning messages are useful information, and it is foolish to comment out use strict to make them go away
Don't call subroutines with an ampersand &. That hasn't been best practice for twenty years now
Lay your code out tidily and cinsistently, so that both you and any people you ask for help can read it easily. As it stands it is impossible to tell where blocks start and end without counting brace characters {...}
Variables should be declared with my as close as possible to their first point of use, and not all at once at the top of the file or subroutine
chomp is necessary only for strings that have been read from the terminal or from a file. It returns the number of characters removed, not the trimmed string
if( $choice =~ /[Yy]/ ) { ... } will check only whether the string contains a Y, so if the operator enters MARRY ME! it will return true. You should use string equality eq to check whether a single Y character has been typed
You shouldn't put scalar variables alone inside double quotes. At best it will make no difference, and just add noise to your code; at worst it will completely change the value of the variable. Just my $kw = $IMS_Message is correct
Unless you require non-sequential access to the contents of a file, it is best to use a while loop to read and process it line by line, rather than read the whole thing into an array and process each element of the array. This also allows you to use the built-in line number variable $. instead of implementing your own $l
The main problem is that you have derived $search from the result of chomp $kw, which sets $search to the number of characters removed by chomp. This is always zero because $kw is a copy of $IMS_Message, which has no newline at the end. That means you are checking all the lines of every file for the character 0, and not for the message that you intended. The correct way is my $search = quotemeta($kw) which you had in place but have commented out, presumably as a result of your policy of "debugging by guesswork"
Fixing these things, your code should look something like this
my $search = qr/\Q$kw/;
for my $file ( grep { -f } glob '*main_log' ) {
open my $fh, '<', $file or die qq{Unable to open "$file" for input: $!};
while ( <$fh> ) {
if ( /$search/ ) {
printf "Found keyword %s in file %s, line %d: %s\n", $kw, $file, $., $_;
last;
}
}
}
I have a file with almost 1,500 names of Marvel heroes, each name in new line. I have to ask user what his favourite hero is and find out if it's a hero from the list or not. Here's what I have right now. It doesn't work: I can guess only the last hero from the list. For the rest it just prints that they are not on the list.
print "Whats your favourite hero?\n";
my $hero = <stdin>;
chomp $hero;
open FILE, "<list_marvel.txt";
my #marvel = <FILE>;
chomp(#marvel);
my $result = 0;
foreach (#marvel) {
if ($_ eq $hero);
}
if ($result == 1) {
print "That hero is on the list";
}
else {
print "$hero is not on the list.\n";
}
Here are two files:
-Perl code : Perl Code
-List of heroes : List
Your program has a syntax error and won't compile. It certainly won't find only the last name on the list
The main problem is that you never set $result, and if($_ eq $hero) should be something like $result = 1 if($_ eq $hero)
You must always use strict and use warnings at the top of every Perl program you write. It is an enormous help in finding straighforward problems
Here's a working version
use strict;
use warnings;
my $filename = 'list_marvel.txt';
open my $fh, '<', $filename or die qq{Unable to open "'list_marvel.txt'": $!};
print "Whats your favourite hero? ";
my $hero = <>;
chomp $hero;
my $found;
while ( <$fh> ) {
chomp;
if ( $_ eq $hero ) {
++$found;
last;
}
}
print $found ? "$hero is on the list\n" : "$hero is not on the list";
You don't set $result anywhere to true.
Make your foreach loop like this:
foreach(#marvel){
$result = $_ eq $hero;
}
or
foreach (#marvel){
$result = 1 if $_ eq $hero
}
You forgot to increment your $result. If you indent your code properly, it is easier to see.
foreach (#marvel) {
# here something is missing
if ( $_ eq $hero );
}
Add $result++ if $_ eq $hero; in the foreach.
You should always use strict and use warnings. That would have told you about a syntax error near );.
Also consider using the three argument open with lexical filehandles.
Rewritten it looks like this:
use strict;
use warnings;
use feature 'say'; # gives you say, which is print with a newline at the end
say "What's you favourite hero?";
my $hero = <STDIN>;
chomp $hero;
# alsways name variables so it's clear what they are for
my $found = 0;
# die with the reason of error if something goes wrong
open my $fh, '<', 'list_marvel.txt' or die $!;
# read the file line by line
while ( my $line = <$fh> ) {
chomp $line;
if ( $line eq $hero ) {
# increment so we know we 'found' the hero in the list
$found++;
# stop reading at the first hit
last;
}
}
close $fh;
# no need to check for 1, truth is enough
if ( $result ) {
say "That hero is on the list.";
}
else {
say "$hero is not on the list.";
}
First, you miss setting the $result at around if($_ eq $hero).
Then, you may wish to make you comparison case insensitive. This would require a regular expression, e.g.:
$result = 1 if (/^$hero$/i);
Just modified your code. After if condition increment $result. Always use use strict and use warnings and always use 3 arguments to open a file.
use strict;
use warnings;
print "Whats your favourite hero?\n";
my $hero = <stdin>;
chomp $hero;
open FILE, "<", "list_marvel.txt" or die $!;
chomp (my #marvel = <FILE>);
close FILE;
my $result = 0;
foreach my $name (#marvel)
{
if($name eq $hero)
{
$result++;
}
}
if ($result == 1)
{
print "That hero is in the list.\n";
}
else
{
print "$hero is not in the list.\n";
}
This will take a single user entry from STDIN. It will run through the file of hero names, and if one matches the user entry it will print the name and exit the loop. If the name is not found it will tell you:
use warnings;
use strict;
open my $file1, '<', 'input.txt' or die $!;
print "Enter hero: ";
chomp(my $hero = <STDIN>);
my $result = 0;
while(<$file1>){
chomp;
if (/$hero/){
print "$_\n";
$result++;
last;
}
}
print "hero not in list\n" if $result == 0;
I'm trying to clean up a directory that contains a lot of sub directories that actually belong in some of the sub directories, not the main directory.
For example, there is
Main directory
sub1
sub2
sub3
HHH
And HHH belongs in sub3. HHH has multiple text files inside of it (as well as some ..txt and ...txt files that I would like to ignore), and each of these text files has a string
some_pattern [sub3].
So, I attempted to write a script that looks into the file and then moves it into its corresponding directory
use File::Find;
use strict;
use warnings;
use File::Copy;
my $DATA = "D:/DATA/DATA_x/*";
my #dirs = grep { -d } glob $DATA;
foreach (#dirs) {
if ($_ =~ m/HHH/) {
print "$_\n";
my $file = "$_/*";
my #files = grep { -f } glob $file;
foreach (#files) {
print "file $_\n";
}
foreach (#files) {
print "\t$_\n";
my #folders = split('/', $_);
if ($folders[4] eq '..txt' or $folders[4] eq '...txt') {
print "$folders[4] ..txt\n";
}
foreach (#folders) {
print "$_\n";
}
open(FH, '<', $_);
my $value;
while (my $line = <FH>) {
if ($line =~ m/some_pattern/) {
($value) = $line =~ /\[(.+?)\]/;
($value) =~ s/\s*$//;
print "ident'$value'\n";
my $new_dir = "$folders[0]/$folders[1]/$folders[2]/$value/$folders[3]/$folders[4]";
print "making $folders[0]/$folders[1]/$folders[2]/$value/$folders[3]\n";
print "file is $folders[4]\n";
my $new_over_dir = "$folders[0]/$folders[1]/$value/$folders[2]/$folders[3]";
mkdir $new_over_dir or die "Can't make it $!";
print "going to swap\n '$_'\n for\n '$new_dir'\n";
move($_, $new_dir) or die "Can't $!";
}
}
}
}
}
It's saying
Can't make it No such file or directory at foo.pl line 57, <FH> line 82.
Why is it saying that it won't make a file that doesn't exist?
A while later: here is my final script:
use File::Find;
use strict;
use warnings;
use File::Copy;
my $DATA = "D:/DATA/DATA_x/*";
my #dirs = grep { -d } glob $DATA;
foreach (#dirs) {
if ($_ =~ m/HHH/) {
my $value;
my #folders;
print "$_\n";
my $file = "$_/*";
my #files = grep { -f } glob $file;
foreach (#files) {
print "file $_\n";
}
foreach (#files) {
print "\t$_\n";
#folders = split('/', $_);
if ($folders[4] eq '..txt' or $folders[4] eq '...txt') {
print "$folders[4] ..txt\n";
}
foreach (#folders) {
print "$_\n";
}
open(FH, '<', $_);
while (my $line = <FH>) {
if ($line =~ m/some_pattern/) {
($value) = $line =~ /\[(.+?)\]/;
($value) =~ s/\s*$//;
print "ident'$value'\n";
}
}
}
if($value){
print "value $value\n";
my $dir1 = "/$folders[1]/$folders[2]/$folders[3]/$folders[4]/$folders[5]";
my $dir2 = "/$folders[1]/$folders[2]/$folders[3]/$folders[4]/$value";
system("cp -r $dir1 $dir2");
}
}
}
}
This works. It looks like part of my problem from before was that I was trying to run this on a directory in my D: drive--when I moved it to the C: drive, it worked fine without any permissions errors or anything. I did try to implement something with Path::Tiny, but this script was so close to being functional (and it was functional in a Unix environment), that I decided to just complete it.
You really should read the Path::Tiny doccu. It probably contains everything you need.
Some starting points, without error handling and so on...
use strict;
use warnings;
use Path::Tiny;
my $start=path('D:/DATA/DATA_x');
my $iter = path($start)->iterator({recurse => 1});
while ( $curr = $iter->() ) {
#select here the needed files - add more conditions if need
next if $curr->is_dir; #skip directories
next if $curr =~ m/HHH.*\.{2,3}txt$/; #skip ...?txt
#say "$curr";
my $content = $curr->slurp;
if( $content =~ m/some_pattern/ ) {
#do something wih the file
say "doing something with $curr";
my $newfilename = path("insert what you need here"); #create the needed new path for the file ..
path($newfilename->dirname)->mkpath; #make directories
$curr->move($newfilename); #move the file
}
}
Are you sure of the directory path you are trying to create. The mkdir call might be failing if some of the intermediate directories doesn't exist. If your code is robust to ensure that
the variable $new_over_dir contains the directory path you have to create, you can use method make_path from perl module File::Path to create the new directory, instead of 'mkdir'.
From the documentation of make_path:
The make_path function creates the given directories if they don't
exists before, much like the Unix command mkdir -p.
I have a file which consists of three names: daniel, elaine and victoria. If I search for daniel I get "you are not on the list". Could someone kindly point out where my mistake is? Thank you.
#!/usr/bin/perl
#open file
open(FILE, "names") or die("Unable to open file");
# read file into an array
#data = <FILE>;
# close file
close(FILE);
print "Enter name\n";
$entry = <STDIN>;
chomp $entry;
if (grep {$_ eq $entry} #data)
{
print "You are on the list $entry";
}
else
{
print "Your are not on the list";
}
You need to chomp (remove new line character from the end of each string) data from the file too:
chomp #data;
if (grep {$_ eq $entry} #data) {
print "You are on the list $entry";
} else {
print "Your are not on the list";
}
change this
if (grep {$_ eq $entry} #data)
to this
if (grep {$_ =~ m/^$entry\b/i} #data)
remove the i if you specifically want it to be case sensitive.
I'm trying to print a character from a file each time I get a char as input.
My problem is that it prints the whole line. I know it's a logic problem, I just can't figure out how to fix it.
use Term::ReadKey;
$inputFile = "input.txt";
open IN, $inputFile or die "I can't open the file :$ \n";
ReadMode("cbreak");
while (<IN>) {
$line = <IN>;
$char = ReadKey();
foreach $i (split //, $line) {
print "$i" if ($char == 0);
}
}
Move the ReadKey call into the foreach loop.
use strictures;
use autodie qw(:all);
use Term::ReadKey qw(ReadKey ReadMode);
my $inputFile = 'input.txt';
open my $in, '<', $inputFile;
ReadMode('cbreak');
while (my $line = <$in>) {
foreach my $i (split //, $line) {
my $char = ReadKey;
print $i;
}
}
END { ReadMode('restore') }
Your original code has 3 problems:
You only read the character once (outside the for loop)
You read 1 line from input file when testing while (<IN>) { (LOSING that line!) and then another in $line = <IN>; - therefore, only read even #d lines in your logic
print "$i" prints 1 line with no newline, therefore, you don't see characters separated
My scrip reads all the files in a directory, puts then in a list, chooses a random file from the given list.
After that, each time it gets an input char from the user, it prints a char from the file.
#!C:\perl\perl\bin\perl
use Term::ReadKey qw(ReadKey ReadMode);
use autodie qw(:all);
use IO::Handle qw();
use Fatal qw( open );
STDOUT->autoflush(1);
my $directory = "codes"; #directory's name
opendir (DIR, $directory) or die "I can't open the directory $directory :$ \n"; #open the dir
my #allFiles; #array of all the files
while (my $file = readdir(DIR)) { #read each file from the directory
next if ($file =~ m/^\./); #exclude it if it starts with '.'
push(#allFiles, $file); #add file to the array
}
closedir(DIR); #close the input directory
my $filesNr = scalar(grep {defined $_} #allFiles); #get the size of the files array
my $randomNr = int(rand($filesNr)); #generate a random number in the given range (size of array)
$file = #allFiles[$randomNr]; #get the file at given index
open IN, $file or die "I can't open the file :$ \n"; #read the given file
ReadMode('cbreak'); #don't print the user's input
while (my $line = <IN>) { #read each line from file
foreach my $i (split //, $line) { #split the line in characters (including \n & \t)
print "$i" if ReadKey(); #if keys are pressed, print the inexed char
}
}
END {
ReadMode('restore') #deactivate 'cbreak' read mode
}