perl -e in ssh

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

Replies are listed 'Best First'.
Re: perl -e in ssh by ikegami (Patriarch) on Apr 13, 2010 at 16:46 UTC
Look where your single quotes start and end in the second command. Completely different from the first command.	[reply]
Re: perl -e in ssh by salva (Canon) on Apr 13, 2010 at 17:36 UTC
That's because you have an additional shell in the remote side interpreting escapes and quoting. You need to add an extra level of quoting resulting in... `'perl\\ -e\\ \\\'\\$s\\ \\=\\ shift\\;\\ \\$SIG\\{ALRM\\}\\ \\=\\ sub\ +\ \\{\\ kill\\ INT\\ \\=\\>\\ \\$p\\ \\}\\;\\ exec\$\\@ARGV\$\\ unl +ess\\ \\$p\\ \\=\\ fork\\;\\ alarm\\ \\$s\\;\\ waitpid\\ \\+\\$p\\,\\ + 0\\ \\\'\\ 3\\ \\\'ls\\ -ltr\\\''` [download] Or you can use Net::OpenSSH and forget about this quoting nightmare: `use Net::OpenSSH; my $ssh=Net::OpenSSH->new($server); my $line = $ssh->capture(perl => -e => <<'EOC', 3, 'ls -ltr'); $s = shift; $SIG{ALRM} = sub {kill INT => $p}; exec(@ARGV) unless $p = fork; alarm $s; waitpid $p, 0; EOC` [download] And check also GRID::Machine, that allows to run perl code in remote machines through SSH.	[reply] [d/l] [select]
Re^2: perl -e in ssh by ikegami (Patriarch) on Apr 13, 2010 at 17:59 UTC
Or automate the quoting: sub shell_quote { my $s = @_ ? $_[0] : $_; return $s if $s =~ /^[a-zA-Z0-9-_]+\z/; $s =~ s/'/'\\''/g; return "'$s'"; } my $server = 'localhost'; my $cmd = 'ls -ltra'; my $timeout = 3; my $watchdog = <<'__EOI__'; $t = shift; $SIG{ALRM} = sub { kill INT => $p }; exec(@ARGV) unless $p = fork; alarm $t; waitpid $p, 0 #exit(...) __EOI__ my $watchdog_cmd = join ' ', map shell_quote, perl => "-e$watchdog", $timeout, $cmd; my $ssh_cmd = join ' ', map shell_quote, ssh => $server, $watchdog_cmd; my $output = `$ssh_cmd`; [download] But wouldn't it make more sense to include ssh in the timeout? ... my $ssh_cmd = join ' ', map shell_quote, ssh => $server, $cmd; my $watchdog_cmd = join ' ', map shell_quote, perl => "-e$watchdog", $timeout, $ssh_cmd; my $output = `$watchdog_cmd`; [download] Tested.	[reply] [d/l] [select]
Re^3: perl -e in ssh by Anonymous Monk on Apr 13, 2010 at 18:42 UTC
the above code just prints out ls -ltra instead of the output of the cmd	[reply]
Re^3: perl -e in ssh by Anonymous Monk on Apr 13, 2010 at 19:05 UTC
ikegami the code just blurts out ksh: 4: not found Please guys can point out where I am going wrong.	[reply]
Re^3: perl -e in ssh by Anonymous Monk on Apr 13, 2010 at 19:06 UTC
ikegami the code just blurts out ksh: 4: not found also there is something about this line thats not right $s = s/'/'\\''/g ; Please guys can point out where I am going wrong.	[reply]
Re^4: perl -e in ssh by ikegami (Patriarch) on Apr 13, 2010 at 19:22 UTC
Re^2: perl -e in ssh by Anonymous Monk on Apr 13, 2010 at 17:46 UTC
I dont have OpenSSH module. But I am still getting this error sh: syntax error at line 1: `(' unexpected where else can I correct	[reply]
Re: perl -e in ssh by graff (Chancellor) on Apr 14, 2010 at 01:37 UTC
Given that you have ssh access to the particular server in question, I would expect that you have a home directory there with write permission, where you can store a perl script as an actual file. So why not just put your perl one-liner into a file on the remote server, and make things simple and clear in the local script: $cmd = `ssh server perl my-remote-one-liner`; [download] I couldn't tell from the OP what sort of args the remote one-liner script was expecting for @ARGV. If including those within the back-ticks for the ssh command is complicated, I would switch from using back-ticks to opening a pipeline file handle, so that I could submit the args as separate list elements (not to be interpreted by the remote shell): `{ my @ssh_cmd = qw/ssh server perl my-remote-one-liner arg1 arg2/; open( my $ssh, "-\|", @ssh_cmd ) or die "ssh failed: $!"; local $/; $cmd = <$ssh>; }` [download] Note that the curlies establish scope for the "local" use of slurp mode, and for the shell file handle (using "my" within the block limits the scope for the variable, whether or not you "use strict;" -- but you do use strict, right?	[reply] [d/l] [select]
Re: perl -e in ssh by moritz (Cardinal) on Apr 13, 2010 at 16:42 UTC
What's the error message?	[reply]
Re^2: perl -e in ssh by Anonymous Monk on Apr 13, 2010 at 16:58 UTC
I am running this cmd $line=`ssh server 'perl \-e '\$s = shift; $SIG{ALRM} = sub { kill INT +=> \$p }; exec(@ARGV) unless \$p = fork; alarm \$s; waitpid \$p, 0 ' +3 'ls -ltra' ' `; [download] and I am getting this error `syntax error at -e line 1, near "=" Execution of -e aborted due to compilation errors. sh: =: not found` [download]	[reply] [d/l] [select]
Re^3: perl -e in ssh by moritz (Cardinal) on Apr 13, 2010 at 17:01 UTC
That's a quoting issue: you have `'...'` around the entire perl command which you pass to ssh, and also `'...'` around the -e one liner - that's not going to work. Oh, and this has nothing to do with perl, but everything with the shell. You could try another quoting character, like ", and escape things where necessary.	[reply] [d/l] [select]
Re^4: perl -e in ssh by Anonymous Monk on Apr 13, 2010 at 17:22 UTC
Re^5: perl -e in ssh by moritz (Cardinal) on Apr 13, 2010 at 17:41 UTC