opening a file

[George]

I thought I would use perl instead of fortran to parse a text file, what
with the new m// s/// capabilities at my fingertips.

So it is that I need to open a text file and send it to STDOUT. This may
come across as a contemptable FAQ to some. I've just looked at all the
entries with the string 'file' beginning them in the index of the camel
book, and it's huge and ambiguous to a guy who is not in the native perl
environment, ie, a server, but simply needs to get a little io on windows.

This is what I have so far:

use strict;
use warnings;


my $divider= "%\n" # a percentage sign and a newline


# perl scraper1.pl

In fortran, the snippet would be:

open(unit=50,file='ehp3.txt',form='formatted')
do
read(50,*,iostat=eof) line
if (eof /= 0) exit
write(*,*) trim(line)
end do
close(unit=50)

Thanks for your comment.
--
George

It's going to be the year of the sharp elbow and the quick tongue.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[Jürgen Exner]

I thought I would use perl instead of fortran to parse a text file, what
with the new m// s/// capabilities at my fingertips.

So it is that I need to open a text file

perldoc -f open

and send it to STDOUT.

perldoc -f print

This may
come across as a contemptable FAQ to some. I've just looked at all the
entries with the string 'file' beginning them in the index of the camel
book, and it's huge and ambiguous to a guy who is not in the native perl
environment, ie, a server,

There is no relation between Perl and servers.

but simply needs to get a little io on windows.

This is what I have so far:

use strict;
use warnings;


my $divider= "%\n" # a percentage sign and a newline


# perl scraper1.pl

In fortran, the snippet would be:

I do not speak Fortran, therefore I cannot translate
Maybe you could just describe what your program is meant to achieve, aka
a spec?

jue

 

[Mirco Wahab]

So it is that I need to open a text file and send it to STDOUT. This may
come across as a contemptable FAQ to some. I've just looked at all the
entries with the string 'file' beginning them in the index of the camel
book, and it's huge and ambiguous to a guy who is not in the native perl
environment, ie, a server, but simply needs to get a little io on windows.

This is what I have so far:
use strict;
use warnings;
my $divider= "%\n" # a percentage sign and a newline

Whats meant by 'divider'. Is this the
'input record seperator'. Your fortran
example doesn't give a hint.

In fortran, the snippet would be:
open(unit=50,file='ehp3.txt',form='formatted')
do
read(50,*,iostat=eof) line
if (eof /= 0) exit
write(*,*) trim(line)
end do
close(unit=50)

This is the closest I could get (under strict):

open(50, '<ehp3.txt');
DO:
{ my $line = readline(*50);
if(eof != 0) { exit }
print $line; # no 'write' here
redo DO } # no 'end' possible
close(50)


This is, of course, just for fun and not
really useful ;-) But it works.

The real "perlish" approach to this
problem is already given in the other
responses to your question.

Regards

M.

 

[Ryan McCoskrie]

I thought I would use perl instead of fortran to parse a text file, what
with the new m// s/// capabilities at my fingertips.

So it is that I need to open a text file and send it to STDOUT. This may
come across as a contemptable FAQ to some. I've just looked at all the
entries with the string 'file' beginning them in the index of the camel
book, and it's huge and ambiguous to a guy who is not in the native perl
environment, ie, a server, but simply needs to get a little io on windows.

This is what I have so far:

use strict;
use warnings;


my $divider= "%\n" # a percentage sign and a newline


# perl scraper1.pl

In fortran, the snippet would be:

open(unit=50,file='ehp3.txt',form='formatted')
do
read(50,*,iostat=eof) line
if (eof /= 0) exit
write(*,*) trim(line)
end do
close(unit=50)

Thanks for your comment.

This is all that you need

#The manuals don't really say it but files have their own data type.
#This line creates a variable called file or exits saying that it can't open
#the file with a possible explanation (the $! variable).
open( FILE, "ehp4.txt") || die "Could not open ehp3.txt $!";

#read out one line at a time until the file ends
while( <FILE> ){
print $_; #If you don't specify a file it goes to STDOUT (STandard OUTput)
#The $_ variable is created by the while statement
}

close(FILE); #This might not really be needed


On Unix type systems (Linux and BSD are not called Unix for legal reasons)
all programs are told about a set of files called stdin, stdout and stderr.
These act as the command line input / output (the last one is to prevent
error messages from being confused with normal output).

If you have a choice try switching over to Linux (FreeBSD later perhaps) and
do your programming their. Most of the perl concepts come from that sort
of environment.
I would describe my system (running Fedora Linux version 10) as a born as
PC and perl fits in very well.
The GNU Compiler Collection also has optional FORTRAN support.

 

[George]

perldoc -f open


perldoc -f print

Both of these turn up a lot of information, most of which is overkill for
this purpose. Furthermore, perl's features are simply confusing for me in
that there are so many, and I only need a little text file that's already
on my machine.

It brings up the notion of filehandles, which is fine, but it is something
I only know from C++ and in an MS development environment. I understand
how to open files in C.

There is no relation between Perl and servers.

What language do sysadmins use?

I do not speak Fortran, therefore I cannot translate
Maybe you could just describe what your program is meant to achieve, aka
a spec?

jue

Thanks for your response, jü.

Nominally, I want to delimit Larry Wall's sigs in a manner that will work
for my next identity. They look like:

%%
"And I don't like doing silly things (except on purpose)."
-- Larry Wall in <[email protected]>
%%
: And it goes against the grain of building small tools.
Innocent, Your Honor. Perl users build small tools all day long.
-- Larry Wall in <[email protected]>
%%
/* And you'll never guess what the dog had */
/* in its mouth... */
-- Larry Wall in stab.c from the perl source code
%%

, and I want to take the %% and replace it with $divider.

Otherwise I want to condition the set that this fortran program outputs. I
have no idea what to do with some of these characters.


module arjen2

type solar_system
type(solar_object), dimension), pointer :: object
end type

type solar_object
character(len=20) :: name
integer :: ascent_hour, ascent_minute, ascent_second
integer :: dec_degrees
real :: dec_mins, distance, azimuth, altitude
logical :: ER, UP

end type

end module arjen2

! default precision


integer, parameter:: max = 1023

integer:: ln, istat

character(len=max):: line

open(unit=50,file='eph4.txt')

do
Read(50,'(A)',IOSTAT=istat) line
ln = Len_Trim(line)
If (istat /= 0) Exit
call parser(line, ln)

write(*,*) trim(line)
end do
contains
subroutine parser(line, ln)
use arjen2
integer::ln
character(len=ln):: line

print *, line, ln



end subroutine

endprogram
! g95 eph7.f03 -o r.exe

C:\MinGW\source>g95 eph7.f03 -o r.exe

C:\MinGW\source>r
Sun 18h 41m 55s -23â–‘ 5.4' 0.983 10.215 52.155 Up 48
Sun 18h 41m 55s -23â–‘ 5.4' 0.983 10.215 52.155 Up
Mercury 20h 2m 16s -22â–‘ 12.5' 1.102 22.537 37.668 Up
52
Mercury 20h 2m 16s -22â–‘ 12.5' 1.102 22.537 37.668 Up
Venus 21h 55m 33s -14â–‘ 16.3' 0.795 39.872 11.703 Up 51
Venus 21h 55m 33s -14â–‘ 16.3' 0.795 39.872 11.703 Up
Moon 21h 17m 19s -15â–‘ 2.4' 62.4 ER 36.796 22.871 Up 51
Moon 21h 17m 19s -15â–‘ 2.4' 62.4 ER 36.796 22.871 Up
Mars 18h 11m 59s -24â–‘ 6.1' 2.431 4.552 56.184 Up 48
Mars 18h 11m 59s -24â–‘ 6.1' 2.431 4.552 56.184 Up
Jupiter 20h 3m 35s -20â–‘ 49.4' 6.034 23.867 38.203 Up
52
Jupiter 20h 3m 35s -20â–‘ 49.4' 6.034 23.867 38.203 Up
Saturn 11h 32m 59s +5â–‘ 8.6' 9.018 -47.333 157.471 Set 53
Saturn 11h 32m 59s +5â–‘ 8.6' 9.018 -47.333 157.471 Set
Uranus 23h 21m 30s -4â–‘ 57.9' 20.421 48.328 -18.527 Up 53
Uranus 23h 21m 30s -4â–‘ 57.9' 20.421 48.328 -18.527 Up
Neptune 21h 39m 30s -14â–‘ 22.8' 30.748 38.963 16.599 Up
54
Neptune 21h 39m 30s -14â–‘ 22.8' 30.748 38.963 16.599 Up
Pluto 18h 4m 34s -17â–‘ 44.5' 32.543 7.443 62.142 Up 50
Pluto 18h 4m 34s -17â–‘ 44.5' 32.543 7.443 62.142 Up

This is how the data fits with the declarations:

Pluto : name
18 ascent_hour
4 ascent_minute
34 ascent_second
-17 dec_degrees
44.5 dec_mins
32.543 distance
0 ER
7.443 altitude
62.142 azimuth
1 UP

Sorry about the longish post, but you asked.
--
George

America is a Nation with a mission - and that mission comes from our most
basic beliefs. We have no desire to dominate, no ambitions of empire. Our
aim is a democratic peace - a peace founded upon the dignity and rights of
every man and woman.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[RedGrittyBrick]

Ryan McCoskrie wrote:

I hope you don't mind, I added a few comments to your advice.

always a good start.

You read from ehp3.txt and write to standard output?
You might find Perl's -p option useful.

perl -p -e "#do something with one line" ehp3.txt

This is all that you need

#The manuals don't really say it but files have their own data type.
#This line creates a variable called file or exits saying that it can't open
#the file with a possible explanation (the $! variable).
open( FILE, "ehp4.txt") || die "Could not open ehp3.txt $!";

There is a bug in that line. This is why I prefer to write
my $filename = 'ehp4.txt';
open my $handle, '<', $filename
or die "unable to open '$filename' because $!";

#read out one line at a time until the file ends
while( <FILE> ){
print $_; #If you don't specify a file it goes to STDOUT (STandard OUTput)

"print;" is the same as "print $_;" and shorter and more idiomatic.

#The $_ variable is created by the while statement
}

close(FILE); #This might not really be needed

I think the OP might be looking for something like

perl -p -e "s/%%/%\n/" ehp3.txt

which is roughly equivalent to
-------------------8<------------------------------
#!/usr/bin/perl
use strict;
use warnings;

my $filename = 'ehp3.txt';
open my $handle, '<', $filename
or die "unable to open '$filename' because $!";
while (<$handle>) {
s/%%/%\n/;
print;
}
close $handle;
-------------------8<------------------------------
Untested - caveat emptor.

 

[smallpond]

Both of these turn up a lot of information, most of which is overkill for
this purpose. Furthermore, perl's features are simply confusing for me in
that there are so many, and I only need a little text file that's already
on my machine.

It brings up the notion of filehandles, which is fine, but it is something
I only know from C++ and in an MS development environment. I understand
how to open files in C.

filehandles are a feature of the OS and filesystems across all
languages.
What do you think logical unit means in FORTRAN?

Trying to get started in a language by reading detailed command
descriptions is like learning to paint a forest by asking a botanist
about
the cell structure of trees. Get a copy of "Learning Perl".

 

[cartercc]

I thought I would use perl instead of fortran to parse a text file, what
with the new m// s/// capabilities at my fingertips.

Easy, easy, easy ...

open INFILE, "<nameoffile.txt";
while (<INFILE>) {print;}
close INFILE;

This creates the handle INFILE for the named file in your current
directory and cycles through it line by line, printing each line. To
write the file to an out handle, do this:

open INFILE, "<nameoffile.txt";
open OUTFILE, ">nameofnewfile.txt";
while (<INFILE>) { print OUTFILE;}
close OUTFILE;
close INFILE;

CC.

 

[Jürgen Exner]

Both of these turn up a lot of information, most of which is overkill for
this purpose. Furthermore, perl's features are simply confusing for me in
that there are so many, and I only need a little text file that's already
on my machine.

I strongly suggest you get an introductory book about Perl. Learning the
concepts of programming language by looking at individual commands is
doomed to fail.

Even "Programming Perl", although not a tutorial, explains file handles
and open() on page 12 and 13 already and reading from a file is
introduced informally together with "while"on page 25 and used in
exactly the way you are looking for on page 27.

The standard Perl idiom for reading and looping through a file is

open(MyFile, '<', $MyFileName) or
die "Cannot open $MyFileName for reading because of $!\n";
while (my $line = <MyFile>) {
#process $line here
}
close MyFile or die "Cannot close file because of $!\n";

It brings up the notion of filehandles, which is fine, but it is something
I only know from C++ and in an MS development environment. I understand
how to open files in C.

Well, it's very similar in Perl. You provide a file handle, the mode,
and the name of the file.

What language do sysadmins use?

Whatever fits the bill. But sysadmin and servers only related by
coincidence. While it is true that many servers are maintained by
sysadmins, there are just as many servers not maintained by sysadmins
and just as many sysadmins, who couldn't care less about servers.

Nominally, I want to delimit Larry Wall's sigs in a manner that will work
for my next identity.

What? Are you a nym shifter?

 

[Jürgen Exner]

Easy, easy, easy ...

open INFILE, "<nameoffile.txt";

Most people would suggest to use the three-argument form of open:
open INFILE, '<', 'nameoffile.txt';

Almost all people would strongly suggest to test for failure:
open INFILE, '<', 'nameoffile.txt' or
die "Cannot open nameoffile.txt because $!\n";

jue

 

[Dr.Ruud]

I thought I would use perl instead of fortran to parse a text file, what
with the new m// s/// capabilities at my fingertips.

So it is that I need to open a text file and send it to STDOUT.

You don't, because you can let your OS do that for you:

./filter.pl < input-file > output-file

In your filter.pl you put something like:

#/usr/bin/perl
use strict;
use warnings;

while ( <> ) {
substr $_, 50, -1, "..."
if length > 50;
}
__END__

 

[George]

George wrote:

This is all that you need

#The manuals don't really say it but files have their own data type.
#This line creates a variable called file or exits saying that it can't open
#the file with a possible explanation (the $! variable).
open( FILE, "ehp4.txt") || die "Could not open ehp3.txt $!";

#read out one line at a time until the file ends
while( <FILE> ){
print $_; #If you don't specify a file it goes to STDOUT (STandard OUTput)
#The $_ variable is created by the while statement

I didn't know that.

}

close(FILE); #This might not really be needed


On Unix type systems (Linux and BSD are not called Unix for legal reasons)
all programs are told about a set of files called stdin, stdout and stderr.
These act as the command line input / output (the last one is to prevent
error messages from being confused with normal output).

If you have a choice try switching over to Linux (FreeBSD later perhaps) and
do your programming their. Most of the perl concepts come from that sort
of environment.
I would describe my system (running Fedora Linux version 10) as a born as
PC and perl fits in very well.
The GNU Compiler Collection also has optional FORTRAN support.

Thanks for your response, Ryan. What do you mean by this? I'm well
acquainted with the gfortran and g95 folks; indeed, I use their compilers.
Do you mean support that doesn't take the form of a compiler?

I ran the script in the same directory as the target, and I missed:

C:\MinGW\source>perl faulk1.pl
Could not open ehp3.txt No such file or directory at faulk1.pl line 4.

C:\MinGW\source>dir
Volume in drive C has no label.
Volume Serial Number is 942A-AD55

Directory of C:\MinGW\source


01/04/2009 07:50 PM 566 eph3.txt
01/05/2009 01:57 PM 1,576 eph4.f03
01/06/2009 10:51 PM 532 eph4.txt
01/05/2009 02:11 PM 1,567 eph5.f03
01/06/2009 10:56 PM 730 eph6.f03
01/06/2009 11:15 PM 852 eph7.f03
01/06/2009 04:43 PM 465 eps1.f03
11/27/2003 02:31 PM 13,333 f2kcli.f90
12/14/2008 01:28 PM 2,662 f2kcli.mod
01/09/2009 06:18 PM 538 faulk1.pl
01/30/2000 03:19 PM 1,276 fax.h


C:\MinGW\source>

Any ideas?
--
George

Bring them on.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[George]

open(50, '<ehp3.txt');
DO:
{ my $line = readline(*50);
if(eof != 0) { exit }
print $line; # no 'write' here
redo DO } # no 'end' possible
close(50)

Shoot, I get nothing for output here. I added asymbol to yours, but I
still get nothing. I have to believe that USER ERROR is rearing its head
and laughing at me.

open(50, '<ehp3.txt>');
DO:
{ my $line = readline(*50);
if(eof != 0) { exit }
print $line; # no 'write' here
redo DO } # no 'end' possible
close(50)

# perl faulk3.pl


C:\MinGW\source>perl faulk1.pl
Could not open ehp3.txt No such file or directory at faulk1.pl line 4.

11/30/2008 01:54 AM 17 dump.bat
12/13/2008 01:13 PM 0 e
12/13/2008 01:07 PM 455,220 e.exe
02/06/2000 11:00 AM 18,733 encode.c
12/06/2008 08:18 PM 18,763 encode1.c
12/31/2008 07:14 PM 79 eph1.f03
12/31/2008 06:32 PM 1,098 eph1.txt
01/02/2009 12:43 AM 672 eph2.f03
12/31/2008 06:52 PM 217 eph2.txt
01/03/2009 07:23 PM 1,807 eph3.f03
01/04/2009 07:50 PM 566 eph3.txt
01/05/2009 01:57 PM 1,576 eph4.f03
01/06/2009 10:51 PM 532 eph4.txt
01/05/2009 02:11 PM 1,567 eph5.f03
01/06/2009 10:56 PM 730 eph6.f03
01/06/2009 11:15 PM 852 eph7.f03
01/06/2009 04:43 PM 465 eps1.f03
11/27/2003 02:31 PM 13,333 f2kcli.f90
12/14/2008 01:28 PM 2,662 f2kcli.mod
01/09/2009 06:18 PM 538 faulk1.pl
01/30/2000 03:19 PM 1,276 fax.h
12/12/2008 08:51 PM 2,719 fin1.txt
12/30/2008 10:41 PM 7,683 frank1.txt
01/07/2009 02:24 AM 6,879 frank2.txt

C:\MinGW\source>perl faulk2.pl
unable to open 'ehp3.txt' because No such file or directory at faulk2.pl
line 6.


C:\MinGW\source>perl faulk2.pl
unable to open 'ehp3.txt' because No such file or directory at faulk2.pl
line 6.


C:\MinGW\source>perl faulk3.pl

C:\MinGW\source>perl faulk3.pl

C:\MinGW\source>

??:-(\
--
George

The United States and our allies are determined: we refuse to live in the
shadow of this ultimate danger.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[George]

./filter.pl

C:\MinGW\source> ./filter.pl
'.' is not recognized as an internal or external command,
operable program or batch file.

C:\MinGW\source>
--
George

Freedom itself was attacked this morning by a faceless coward, and freedom
will be defended.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[George]

perldoc -q 'entire file'

Keith,

I seem completely befuddled by bonehead stuff here. An example is that dos
gives me nothing for perldoc; what's more, I find options on the net that
don't seem to be as simple as this task must be.

http://perldoc.perl.org/File/Find.html

OTOH, maybe perl has completely different notions. I'm quite clueless
here. What can I say: I'm George.
--
George

You can fool some of the people all the time, and those are the ones you
want to concentrate on.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[Jürgen Exner]

Shoot, I get nothing for output here. I added asymbol to yours, but I
still get nothing. I have to believe that USER ERROR is rearing its head
and laughing at me.

open(50, '<ehp3.txt>');
DO:
{ my $line = readline(*50);
if(eof != 0) { exit }
print $line; # no 'write' here
redo DO } # no 'end' possible
close(50)

Ouch! This hurts! I suppose some people manage to program in Fortran no
matter what programming language they are using.

Could not open ehp3.txt No such file or directory at faulk1.pl line 4. ^^^^^^^^
[...]
01/04/2009 07:50 PM 566 eph3.txt

^^^^^^^^

Dah!

jue

 

[Jürgen Exner]

C:\MinGW\source> ./filter.pl
'.' is not recognized as an internal or external command,
operable program or batch file.

You might want to learn how to use your OS/command shell.

.\filter.pl

jue

 

[George]

Ouch! This hurts! I suppose some people manage to program in Fortran no
matter what programming language they are using.

That's what they say about fortran, is that you do it in any syntax. If
you don't eventually "give in" to the ethos of a scripting language, you
miss the better part of it. Wir meinen damit daß das abwertend ist,
fortran sonstwo zu üben.

For example, there's one line in a perl script. Mirko's script does well
to entertain my previous notions here. In particular, the unit number in
fortran looks like it works as a file handle for perl. Am I correct that
50 is a perfectly kosher fh here.

That the read avails itself of fifty with one level of indirection is
something that one might expect of a child of C.

Could not open ehp3.txt No such file or directory at faulk1.pl line 4. ^^^^^^^^
[...]
01/04/2009 07:50 PM 566 eph3.txt

^^^^^^^^

Dah!

jue

Ich bin ahnungslos:

C:\MinGW\source>perldoc -q 'entire file'
No documentation for perl FAQ keyword `'entire' found

C:\MinGW\source>perl faulk3.pl

C:\MinGW\source>type eph3.txt
! yesterday
# another comment

Sun 18h 41m 55s -23â–‘ 5.4' 0.983 10.215 52.155 Up
Mercury 20h 2m 16s -22â–‘ 12.5' 1.102 22.537 37.668 Up
Venus 21h 55m 33s -14â–‘ 16.3' 0.795 39.872 11.703 Up
Moon 21h 17m 19s -15â–‘ 2.4' 62.4 ER 36.796 22.871 Up
Mars 18h 11m 59s -24â–‘ 6.1' 2.431 4.552 56.184 Up
Jupiter 20h 3m 35s -20â–‘ 49.4' 6.034 23.867 38.203 Up
Saturn 11h 32m 59s +5â–‘ 8.6' 9.018 -47.333 157.471 Set
Uranus 23h 21m 30s -4â–‘ 57.9' 20.421 48.328 -18.527 Up
Neptune 21h 39m 30s -14â–‘ 22.8' 30.748 38.963 16.599 Up
Pluto 18h 4m 34s -17â–‘ 44.5' 32.543 7.443 62.142 Up

C:\MinGW\source>type faulk3.pl
open(50, '<eph3.txt>');
DO:
{ my $line = readline(*50);
if(eof != 0) { exit }
print $line; # no 'write' here
redo DO } # no 'end' possible
close(50)

# perl faulk3.pl
C:\MinGW\source>


--
George

I believe the most solemn duty of the American president is to protect the
American people. If America shows uncertainty and weakness in this decade,
the world will drift toward tragedy. This will not happen on my watch.
George W. Bush

Picture of the Day http://apod.nasa.gov/apod/

 

[Tim Greer]

ran the script in the same directory as the target, and I missed:

C:\MinGW\source>perl faulk1.pl
Could not open ehp3.txt No such file or directory at faulk1.pl line 4.

C:\MinGW\source>dir
Volume in drive C has no label.
Volume Serial Number is 942A-AD55

Directory of C:\MinGW\source


01/04/2009  07:50 PM               566 eph3.txt

C:\MinGW\source>

Any ideas?

yes, eph.txt and ehp.txt are not the same file name.

 

[Peter J. Holzer]

I'm sure Mirco meant that as a joke.

That's what they say about fortran, is that you do it in any syntax. If
you don't eventually "give in" to the ethos of a scripting language, you
miss the better part of it.

Right. See below.

Wir meinen damit daß das abwertend ist, fortran sonstwo zu üben.

I'm not sure whether this sentence means what you think it means ;-)

For example, there's one line in a perl script. Mirko's script does well
to entertain my previous notions here. In particular, the unit number in
fortran looks like it works as a file handle for perl. Am I correct that
50 is a perfectly kosher fh here.

Not quite. A slight hint that it isn't perfectly kosher is that a "*" is
needed in the argument list to readline to distinguish it from the
number 50.

Use lexical file handles:

open(my $fh, '<ehp3.txt>');
DO:
{ my $line = readline($fh);
if(eof != 0) { exit }
print $line;
redo DO }
close($fh)

Use the three argument form of open:

open(my $fh, '<', 'ehp3.txt>');
DO:
{ my $line = readline($fh);
if(eof != 0) { exit }
print $line;
redo DO }
close($fh)

(which btw, makes it clear that the file name is wrong. You don't want
to open 'ehp3.txt>', but 'ehp3.txt', or rather 'eph3.txt')

Use proper loops instead using redo to jump back to the
beginning of a block.

open(my $fh, '<', 'eph3.txt');
while (my $line = readline($fh)) {
print $line;
}
close($fh)

Aquaint yourself with the operator form of readline.

open(my $fh, '<', 'eph3.txt');
while (my $line = <$fh>) {
print $line;
}
close($fh)

And you might want to use the $_ variable:

open(my $fh, '<', 'eph3.txt');
while (<$fh>) {
print $_;
}
close($fh)

In short: Write Perl, not Perl-disguised-as-Fortran.

And of course you should check for errors:

open(my $fh, '<', 'eph3.txt') or die "cannot open eph3.txt: $!";
while (<$fh>) {
print $_;
}
close($fh)

And you should use variables if you use the same string more than once:

my $filename = 'eph3.txt';
open(my $fh, '<', $filename) or die "cannot open $filename: $!";
while (<$fh>) {
print $_;
}
close($fh)

(this is especially important for error messages. If you misspell a
filename in the call to open, but not in the error message, the error
message is extremely confusing)

hp