i'm new with Perl :)
i'm trying to write a simple script just open a CLI environment ( by executing bash command)
and then send a command to that environment (only that environment familiar with this command)
for example:
my linux is running in HP server machine.
if i would like to see the memory configuration so under root user i need
to execute: 'hpasmcli" and then i well get the following environment :
root#xxx:/>% hpasmcli
HP management CLI for Linux (v2.0)
Copyright 2008 Hewlett-Packard Development Group, L.P.
NOTE: Some hpasmcli commands may not be supported on all Proliant servers.
Type 'help' to get a list of all top level commands.
hpasmcli>
and now the need to enter "show dimm":
NOTE: Some hpasmcli commands may not be supported on all Proliant servers.
Type 'help' to get a list of all top level commands.
hpasmcli> show dimm
then i will get the memory configuration in the server.
so i'm tying to write a Perl script to make this simple task.
i tried to use "expect" and "open(FH,"|/sbin/hpasmcli") but i was able just to log in
to the CLI environment and not to send the command "show dimm"
Thank you for your help!
You might need to flush the output buffer after every write:
open my $CMD, "| /sbin/hpasmcli"
or die "Couldn't pipe output to hpasmcli: $!";
my $old_out = select $CMD;
$| = 1; #perl's autoflush global variable which affects the current output file handle
select $old_out;
print {$CMD} "show dimm";
Related
I'm running a script in solaris 11 with different results depending of the shell used.
The script has an echo redirecting to a file given by an environment value:
echo "STARTING EXEC" >> $FILE
ps. EXEC is just the message the script show, it's not using exec command.
If I execute the script without the variable FILE defined (using /usr/bin/ksh):
./start.sh[10]: : cannot open
and the script continue the execution.
The flags for ksh are:
echo $-
imsuBGEl
But if I change to /usr/xpg4/bin/sh, the script show me the echo in stdout and there is no error shown.
The flags for xpg4 sh are:
echo $-
imsu
I tried to change the flags with set +- (I can't remove El flags, but BG are removed ok), but can't get the same behavior.
Is there anything I can do to get the same result using ksh without cannot open error?
/usr/bin/ksh --version
version sh (AT&T Research) 93u 2011-02-08
I'll want the script keep going, showing the message in stdout, instead of showing the error just like it does now.
Like shellter said in the comments, the good thing to do is to check if the FILE variable is defined before doing anything. This is a script migration from an HPUX to a SOLARIS environment, and client think they must have the same result as before (we unset FILE variable before execution to test it).
You are likely running Solaris 11, not Solaris 64.
Should you want to have your scripts to work under Solaris 11 without having to search everywhere the bogus redirections, you can simply replace all shebangs (first line) by #!/usr/xpg4/bin/sh.
The final solution we are going to take is to install the ksh88 package and use it like default shell (/usr/sunos/bin/ksh). This shell have the same behavior the client had before, and we can let the scripts with no modifications.
The ksh used in solaris 11 is the 93 (http://docs.oracle.com/cd/E23824_01/html/E24456/userenv-1.html#shell-1)
Thanks #jlliagre and #shellter for your help.
Is it possible to run perl script, which is located on a remote server, on that server from Windows? There is a job on a remote server that I want to get done every time I make something on Windows.
You have to have something listening for an instruction to run the script, and then you have to send the instruction.
There are lots of approaches you could take to that, including:
Running an SSH server and then connecting to it from an ssh client on the windows machine
Running an HTTP server, running the script through FastCGI, and then requesting the URL for it from curl or a browser on the Windows machine
Writing a custom protocol, listening on a socket, and then writing a custom client that you run on the Windows machine
Absolutely.
You can use plink to run commands on the server from Windows, assuming the server is running sshd.
plink user#a.domain.ext echo hi
This will print "hi\n" to the standard output.
Substitute /path/to/perl/script for echo above and substitute hi with any command line argument that the script needs.
plink is available here: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
One cautionary personal note from doing this many times is that the environment in which the perl script will be run is much less complete than what you would experience when logging in via a full SSH session and running the command interactively. Many environment variables you would normally expect are unset.
For instance using "set | wc -l" in the command above produces only 39 environment variables defined, but from an interactive SSH session, there are 57 environment variables defined. You have to make sure your perl script isn't depending on an environment variable that hasn't been set. For instance, you may need to use full paths for any modules that it uses, or by using the -I flag in the shebang line, because #INC may not be what you expect it to be.
I am writing a shell script to automate some of the tedious tasks that we perform. I need to ssh to a server and change the PATH variable remotely, have that variable persist for the next commands to be executed. Code below;
sub ab_tier{
my $ssh=Net::SSH::Perl->new($host);
$ssh->login($user2,$user2);
my $PATH;
my($stdout,$stderr,$exit)=$ssh->cmd("export
PATH=/usr/bin/sudo:/local/perl-5.6.1/bin:$PATH");
my($PATH, $stderr, $exit)=$ssh->cmd("echo $PATH");
print $PATH; # Check the path for correctness : does not change
}
However the PATH does not change. Is there another way to implement this or am I doing something wrong. I need to automate tasks so dont think $ssh->shell would help here. Please suggest.
I made changes as per suggestions and everything works fine. However I am noticing another issue, which is occurring when trying to display environment variables.
my $cmd_ref_pri={
cmd0=>"echo $ENV{'HOME'}",
cmd1=>"chmod 777 $ENV{'COMMON_TOP'}/temp"
};
Now I am connecting to a remote server using Net::SSH::Perl and the value returned by $ENV{"HOME"} is the value of the my home directory and not of the remote server. However if I add a command as in :
my $cmd_ref_pri={
cmd0=>"whoami ; echo $ENV{'HOME'}",
cmd1=>"chmod 777 $ENV{'COMMON_TOP'}/temp"
};
Then the user id displayed is of the user using which I ssh to the remote server. I do not have other modules installed and the only one available is Net:SSh:perl hence I am forced to use this.
routine for executing command
sub ssh_cmd{
#$cmd_sub - contains command, $ssh contains object ref
my ($cmd_sub,$ssh)=#_;
my($stdout, $stderr, $exit)=$ssh->cmd("bash",$cmd_sub);
if( $exit !=0){
print $stdout;
print "ERROR-> $stderr";
exit 1;
}
return 0;
}
Any suggestions as to why this could happen ?
cmd() is not passing your commands into one shell. It executes them in separate shells (or without any shell - manual is not clear about it). As soon as you finish your export PATH the shell exits and the new PATH is lost.
Looks like it is possible to pass all the relevant commands to a single shell process as separate lines of $stdin?
my $stdin='export A=B
echo $A
';
$ssh->cmd("bash",$stdin);
This would work just like on interactive login (but without terminal control, so commands that talk directly to terminal would likely fail).
Anyway Net::SSH::Perl does not look like the best tool for the job. I would rather use expect for automation.
Set PATH on every command call:
$ssh->cmd('PATH=/usr/bin/sudo:/local/perl-5.6.1/bin:$PATH echo $PATH');
And BTW, Net::SSH::Perl is not being maintained anymore, nowadays Net::SSH2 and Net::OpenSSH are better alternatives.
Write commands to a remote temp file, then execute that one. Or, skip the $PATH thing and use the full path for subsequent commands (assuming you know it).
The server perl script - with its required packages - works locally by the user "my_user".
But if I run the script remotely (ssh), I need to export PERL5LIB=/usr/local/share/perl/5.10.0/my_modules before calling the perl script to get it working.
Why this and how can I turn around this in order to avoid exporting PERLIB each time I need to call a remote perl script ?
WORKING :
ssh my_user#remote_server "export PERL5LIB=/usr/local/share/perl/5.10.0/my_modules; /cgi-bin/my_perl_script.pl --option1 foo --option2 '*';"
NOT WORKING :
ssh my_user#remote_server "/cgi-bin/my_perl_script.pl --option1 foo --option2 '*';"
returns :
Can't locate my_package1.pm in #INC
That might be rather an ssh question than a strict perl point : why the remote user running the perl script does not inherit from its ENV local datas.
Thx
As suggested by #mu_is_too_short (no friction is good as well), and linking to a more detailed explanation here, there are different types of shells : "the SSH command execution shell is a non-interactive shell, whereas your normal shell is either a login shell or an interactive shell".
So the solution is what I did on purpose (eg adding "export PERL5LIB" before running the script), or better, source the whole environement from the remote user to run the remote shell with the expected behavior.
I have a Perl script running on a Windows machine. I need this script to open a ssh session to a remote Unix machine, and to be able to execute certain commands on that Unix machine and to be able to get the output returned from these commands.
These commands are generated during the run-time of the script, and there are many of them executed at different times.
How can I do it?
Approach 1: Use CYGWIN: http://perlwin32ssh.blogspot.com/2007/07/test_4418.html
Approach 2: Use Net::SSH::W32Perl module.
This is one thread discussing how to install it: http://code.activestate.com/lists/perl-win32-users/29180/ (It seems to require downloading custom version of the module)
This thread should help with the problems arising from dependencies on math libraries needed for ssh calculations: http://www.issociate.de/board/post/494356/I%27m_trying_to_install_%27Net::SSH::Perl%27_on_a_Windows_Box..html
Caveat emptor: I never installed this, the above is just result of some analysis of google results.
#!/usr/bin/perl
system("ssh foo 'ls -l'");
Or go through the hassle of using ptmx(4) on the local side and ssh -t for remote.