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unix command 1
- Thread starter tazhicham
- Start date
-
1
- #2
Hello taz
There are a few ways to do this. Which one you use depends upon what you'd like to do with the output of commands you run - if you'd like to do anything at all.
system() function
system("ls -l"
;
That runs the ls -l command, the output will appear on your screen. This is the easiest way to run an external command. It's difficult to do anything with the output though.
backticks
$a = `ls -l`;
or
@a = `ls -l`;
Backticks let you run a command and capture the output all in one go so that you can process it later.
The first example puts all of the output of ls -l in one Perl variable, a scalar variable as they say.
The second example puts each line of the output into an element of the @a array. The first line of the output from ls -l will be in $a[0], the second in $a[1] and so on.
Using a pipe.
This is a way of processing data from a command as it gets produced by that command, you don't have to wait for the command to finish before working with the data. It's useful when you're running a command that might take a long while to finish - or maybe it will never finish and you need to process data from it constantly.
open(OP, "ls -l |"
while(<OP>){
print $_;
}
close OP;
I hope that this goes someway to answering your query.
Mike
Want to get great answers to your Tek-Tips questions? Have a look at faq219-2884
It's like this; even samurai have teddy bears, and even teddy bears get drunk.
There are a few ways to do this. Which one you use depends upon what you'd like to do with the output of commands you run - if you'd like to do anything at all.
system() function
system("ls -l"
;That runs the ls -l command, the output will appear on your screen. This is the easiest way to run an external command. It's difficult to do anything with the output though.
backticks
$a = `ls -l`;
or
@a = `ls -l`;
Backticks let you run a command and capture the output all in one go so that you can process it later.
The first example puts all of the output of ls -l in one Perl variable, a scalar variable as they say.
The second example puts each line of the output into an element of the @a array. The first line of the output from ls -l will be in $a[0], the second in $a[1] and so on.
Using a pipe.
This is a way of processing data from a command as it gets produced by that command, you don't have to wait for the command to finish before working with the data. It's useful when you're running a command that might take a long while to finish - or maybe it will never finish and you need to process data from it constantly.
open(OP, "ls -l |"
;while(<OP>){
print $_;
}
close OP;
I hope that this goes someway to answering your query.
Mike
Want to get great answers to your Tek-Tips questions? Have a look at faq219-2884
It's like this; even samurai have teddy bears, and even teddy bears get drunk.
- Thread starter
- #3
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