All Questions
199
questions
3
votes
1
answer
215
views
How to launch interactive commands from Perl while allowing Perl to parse the command output
The Question
How do I change a Perl script to allow for both unattended and
interactive execution of the child process, such that in the
interactive scenario, the user interacts with the GDB just like ...
- 2,870
3
votes
1
answer
160
views
How can I detect end of file on a pipe in a Perl script?
In a Perl script, I am running another process (openssl) and communicating with it via pipes. I run openssl with IPC::Run::start.
$openssl_stdin_handle = Symbol::gensym();
$openssl_stdout_handle = ...
- 341
1
vote
3
answers
144
views
Piping stdout to stdin in perl between multiple functions (like cmd1 | cmd2 | cmd3 in shell)
I need to process large streams of data. Streams larger than would fit in RAM.
The stream needs to have multiple transformations applied to it in sequence. A pipeline of asynchronously executing tasks ...
- 33.1k
0
votes
1
answer
216
views
Save STDIN to file in Perl?
I'm trying to use Perl to:
wait until at least 1 byte arrives on STDIN
read all of STDIN and save it to a file as binary (to be UTF-8 compatible)
My attempts:
# read STDIN into a string/buffer and ...
- 4,783
1
vote
2
answers
236
views
command to validate input in a pipeline then pass it on?
I want to inject a command into a pipeline that just validates the input at that point, passing it on if it's valid. If it isn't valid nothing could be passed on, or perhaps a custom-defined error ...
- 457
0
votes
1
answer
75
views
How do we use the piped command in Perl? [closed]
This is the command -
$ find /var/opt/ -type f -mtime -1 -print0 | du -s |cut -f1
498172
When I run from the command line in Linux it gives output - the size.
I want to run the same command from ...
- 135
1
vote
1
answer
106
views
Cannot capture stdout/stderr in Perl on Windows using pipes
I'm trying to write a function that spawns a subprocess, allows us to capture stdout and stderr separately, and returns it exit status. I know there are libraries for this, but let's make it a ...
- 3,583
2
votes
3
answers
886
views
How do I use Perl IPC::Run3 to read stdout and stderr from a subprocess?
I want to run a make command from a Perl script so I can capture its stdout and stderr streams. I know I could use open(MAKE, "make 2>&1 |") but this gives problems building the ...
- 4,871
2
votes
0
answers
292
views
Perl threads sometimes get stuck (some of them waiting for futex)
I'm facing a problem with a multi-threaded Perl application that I'm trying to run (on Redhat 7.4 using Perl 5.10.1). The problem has been reproduced through the setup below (setup is similar to the ...
- 31
3
votes
2
answers
441
views
How to pipe to and read from the same tempfile handle without race conditions?
Was debugging a perl script for the first time in my life and came over this:
$my_temp_file = File::Temp->tmpnam();
system("cmd $blah | cmd2 > $my_temp_file");
open(FIL, "$...
- 5,269
3
votes
2
answers
175
views
How make open function use bash instead of sh?
I want to use bash instead of sh when I use the open function. For instance:
sub run_cmd {
my ($cmd) = @_;
my $fcmd;
print("Run $cmd\n");
open($fcmd, "$cmd |");
...
- 2,052
1
vote
1
answer
197
views
Perl: closing child process fails when file handle to child/pipe is aliased
I've read all the perl documentation on open, close and IPC and read a number of related forum threads, but still have been unable to figure out what I'm doing wrong. To start with I created this ...
- 11
0
votes
4
answers
117
views
Process a file containing a collection of JSON strings
(Title edited. The original title: "json content: print out parts of it as is, pipe parts of it to get human readable timestamps, output from the same command")
I have a json alike content in a file:
...
- 81
5
votes
1
answer
372
views
Does opening a pipeline in Perl involve a shell?
If I do this in a Perl script on a Unix/Linux system:
open(my $fh, 'cat|');
is a shell involved? And if not, what about this:
open(my $fh, 'cat -v|');
I would like to avoid a shell, if possible, ...
- 312
1
vote
1
answer
189
views
Read X Number of Bytes from Pipe in Perl [closed]
What is the best way to read x number of binary bytes from a pipe in Perl? Using sysread returns only 8K bytes. I need to read around 1GB of bytes from the pipe before continuing with the rest of ...
- 2,335