Simple awk question

[czah7]

I am very new to PERL. Like first week I've tried using it. In bash I can do this:

echo hello1 hello2 hello3|awk '{ print $1 }' and it prints "hello1"

In a script I need to do a similar thing, but the data is inside a variable.

For example: echo $variable |awk '{ print $1 }'

I've tried several variations, I know I'm missing something very simple...

$time = print $error|print $F[0]; or $time = system(echo $error) | system( awk '{print $1}'); or $time = print $error | system(awk '{ print $1 }');

None work. So to make it simple.

#!/usr/bin/perl
$error = '2014-06-04T15:24:21-05:00 syslog_dp [0x80e00099][ftp][error]
+ secure-backup(FBB): trans(5487)';
$time = print $error|print $F[0];

$time should then = 2014-06-04T15:24:21-05:00

[no_slogan]

Perl has awk functionality built in, so you can do something like:

$x = "ack thpt barf";
@fields = split " ", $x;
print $fields[0], "\n";

[czah7]

I think this is exactly what I need! Thanks.

[czah7]

On second thought. Almost! I need $fields to now be just that first field. Not just print the first field, it now needs to be a new variable.

I tried

$fields = print $fields[0], "\n";

close but no cigar, yet.

[Bloodnok]

How about echo $variable | perl -nae 'print $a[0]' or possibly perl -e 'print((split /\s+/, "'$variable'")[0])' ?

Update:

Very many thanx to LanX - modifed 2nd suggestion to correct parenthesis, but ignored nested quotes comment since they are most definitely deliberate - without them, perl would split the string '$variable' whereas with them, the shell expands the shell variable and perl then splits that string.

[LanX]

perl -e 'print (split /\s+/, "'$variable'")[0]'

nested quotes? :)

update

and the brackets belong to print , (...)[0] won't work.

[LanX]

Perl doesn't know echo only print

What you seem to want is open with a pipe-symbol¹ to write to awk's STDIN.

Calling awk from Perl is somehow strange, though, Perl was primarily designed to replace awk and sed .

update

if you just wanna pass a handful of variables better use arguments in backticks

 my $result = `awk $var1 $var2`;

but I don't know much about awk (cause I don't need to ;-)

¹) like in

        
open(my $awk, "|awk >Tmp$$") # $$ is our process id
   or die "Can't start awk: $!";
print $awk $var1, $var2;
close $awk;

[RonW]

Calling awk from Perl is somehow strange, though, Perl was primarily designed to replace awk and sed .

For what it's worth, there is the a2p tool to convert AWK scripts into Perl. It can be helpful in transitioning to Perl from AWK.

[GotToBTru]

Please provide enough of your perl code to show what the variables are, the input, and what you expect the output to look like.

echo $variable | awk '{print $1}'

is redundant. Save yourself some typing.

echo $variable

Okay, you are probably trying to do more than just print a single variable, but that's all I have to go on from what you've given me so far. Well, there's an array called @F and scalars called $time and $error, but it's anyone's guess as to what they contain or what they are for.

[czah7]

So to make it simple.

#!/usr/bin/perl
$error = '2014-06-04T15:24:21-05:00 syslog_dp [0x80e00099][ftp][error]
+ secure-backup(FBB): trans(5487)';
$time = print $error|print $F[0];

$time should then = 2014-06-04T15:24:21-05:00

[fishmonger]

$time = print $error|print $F[0];

That attempt to pipe one statement to another statement like you would do when piping shell commands won't work.

You've already been shown a couple ways to extract the datestamp.

$error = '2014-06-04T15:24:21-05:00 syslog_dp [0x80e00099][ftp][error]
+ secure-backup(FBB): trans(5487)';

$time = (split /\s/, $error)[0];
print $time, "\n";

# or you could do this:
($time) = $error =~ /^(\S+)/;
print $time, "\n";