how to send input to stdin automatically?

skyworld_chen has asked for the wisdom of the Perl Monks concerning the following question:

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Re: how to send input to stdin automatically? by Utilitarian (Vicar) on Dec 18, 2012 at 09:04 UTC
As a general rule you should enable ssh key exchange on your cvs repository and then the question becomes moot. From your development machine: `ssh-keygen -t dsa (accept the default for all queries) $ cat ~/.ssh/id_dsa.pub \| ssh ${repository_host} "mkdir -p .ssh ; cat +>> .ssh/authorized_keys" (enter your password) $ ssh ${repository_host}echo (answer "yes") $ ssh ${repository_host} echo (Nothing should happen, you should just get your prompt back)` [download] You need to set the following environment variables (put them in your .profile or .bashrc) before you can run any cvs command: `$ export CVS_RSH=ssh $ export CVSROOT=${username}@${repositry_host}:/path/to/cvsroot/` [download] Hope that helps `print "Good ",qw(night morning afternoon evening)[(localtime)[2]/6]," fellow monks."`	[reply] [d/l] [select]
Re^2: how to send input to stdin automatically? by skyworld_chen (Acolyte) on Dec 18, 2012 at 12:46 UTC
Hi all, I'm a new comer for Perl, both SSH and Expect seems difficult to me. I need some time to understand them. Thanks for all of your kind replies.	[reply]
Re: how to send input to stdin automatically? by tobyink (Canon) on Dec 18, 2012 at 07:56 UTC
Many programs that read passwords do not read them from STDIN - they read keystrokes from the terminal. If CVS is one of those, then sending data to its STDIN will not help you. But yes, you can run a program from Perl and pipe data to its STDIN... `open my $pipe, '\|-', 'some-program arg1 arg2'; print {$pipe} "some data\n"; close $pipe;` [download] If you also need to read from that program's STDOUT or STDERR, check out IPC::Open2, IPC::Open3 or System::Command. `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l]
Re^2: how to send input to stdin automatically? by salva (Canon) on Dec 18, 2012 at 09:06 UTC
`ssh` (as most programs asking for a password) does not read the password from stdin but from the process tty, so not opening a pipe neither using any of the modules you have named will work. The usual solution to automate password authentication is to use Expect.	[reply] [d/l]
Re^2: how to send input to stdin automatically? by skyworld_chen (Acolyte) on Dec 18, 2012 at 08:37 UTC
Hi tobyink, thanks for your kind reply. You are right, I do need to send password to keyboard, not STDIN. I have tried code you suggested, but the linux still asks for the password. My code is as this: `#!/usr/bin/perl open my $pipe,'\|-', 'cvs update'; print {$pipe} "my_password\n"; close $pipe;` [download] did I miss something? thanks.	[reply] [d/l]
Re: how to send input to stdin automatically? by graff (Chancellor) on Dec 18, 2012 at 08:43 UTC
I think you'll need to look at Expect (or one of its variants).	[reply]