This feels like a really silly problem but I just can't figure it out. I am writing an AGI script in Perl using Asterisk::AGI which needs to invoke Festival to read some text to the caller. I know that in the dialplan I can say
Festival('Hello caller','any')
and it will say 'Hello caller' and allow interruption by any key. The trick is doing that from the AGI script. If I do this:
$agi->exec('Festival', '"Hello caller"')
It will say 'Hello caller'. No problem. But I can't get it to deal with the potential for key interruption. It looks kind of like a second parameter, but also kind of not like one. I tried
$agi->exec('Festival', '"Hello caller"', 'any')
And it seems to ignore it completely (no key interruption takes place). I also tried
$agi->exec('Festival', q{"Hello caller",'any'})
And it says the 'any' bit, which leads me to be seriously confused about the quoting (the double quotes inside the string I pass was the only way I could get it to do more than say the first word).
$agi->exec('Festival', q{"Hello caller", 'any'})
Just ignores the 'any' bit entirely.
The only resources online that mention using Festival from an AGI script all talk about invoking it externally, saving it to a temporary file and then playing that back. Do I really have to go down that path? Shouldn't I be able to run any dialplan application at all with any arguments I like from an AGI?
Yes, you are able to execute applications like in the dialplan, with AGI exec.
You have to separate arguments with a Pipe (|) character.
Example exec Dial with options (examples/agi-enum.agi)
if ($option) {
$option .= '|' . $DEFAULTTIMEOUT if ($DEFAULTTIMEOUT);
$AGI->verbose("Executing Dial $option\n",3);
$res = $AGI->exec('Dial', $option);
}
For Festival, it should work like this:
$agi->exec('Festival', '"Hello caller"|"any"');
or
$agi->exec('FESTIVAL "Hello caller"|"any"');
Related
I am trying to identify misspelled words with Aspell via Perl. I am working on a Linux server without administrator privileges which means I have access to Perl and Aspell but not, for example, Text::Aspell which is a Perl interface for Aspell.
I want to do the very simple task of passing a list of words to Aspell and having it return the words that are misspelled. If the words I want to check are "dad word lkjlkjlkj" I can do this through the command line with the following commands:
aspell list
dad word lkjlkjlkj
Aspell requires CTRL + D at the end to submit the word list. It would then return "lkjlkjlkj", as this isn't in the dictionary.
In order to do the exact same thing, but submitted via Perl (because I need to do this for thousands of documents) I have tried:
my $list = q(dad word lkjlkjlkj):
my #arguments = ("aspell list", $list, "^D");
my $aspell_out=`#arguments`;
print "Aspell output = $aspell_out\n";
The expected output is "Aspell output = lkjlkjlkj" because this is the output that Aspell gives when you submit these commands via the command line. However, the actual output is just "Aspell output = ". That is, Perl does not capture any output from Aspell. No errors are thrown.
I am not an expert programmer, but I thought this would be a fairly simple task. I've tried various iterations of this code and nothing works. I did some digging and I'm concerned that perhaps because Aspell is interactive, I need to use something like Expect, but I cannot figure out how to use it. Nor am I sure that it is actually the solution to my problem. I also think ^D should be an appropriate replacement for CTRL+D at the end of the commands, but all I know is it doesn't throw an error. I also tried \cd instead. Whatever it is, there is obviously an issue in either submitting the command or capturing the output.
The complication with using aspell out of a program is that it is an interactive and command-line driver tool, as you suspect. However, there is a simple way to do what you need.
In order to use aspell's command list one needs to pass it words via STDIN, as its man page says. While I find the GNU Aspell manual a little difficult to get going with, passing input to a program via its STDIN is easy enough and we can rewrite the invocation as
echo dad word lkj | aspell list
We get lkj printed back, as due. Now this can run out of a program just as it stands
my $word_list = q(word lkj good asdf);
my $cmd = qq(echo $word_list | aspell list);
my #aspell_out = qx($cmd);
print for #aspell_out;
This prints lines lkj and asdf.
I assemble the command in a string (as opposed to an array) for specific reasons, explained below. The qx is the operator form of backticks, which I prefer for its far superior readability.
Note that qx can return all output in a string, if in scalar context (assigned to a scalar for example), or in a list when in list context. Here I assign to an array so you get each word as an element (alas, each also comes with a newline, so may want to do chomp #aspell_out;).
Comment on a list vs string form of a command
I think that it's safe to recommend to use a list-form for a command, in general. So we'd say
my #cmd = ('ls', '-l', $dir); # to be run as an external command
instead of
my $cmd = "ls -l $dir"; # to be run as an external command
The list form generally makes it easier to manage the command, and it avoids the shell altogether.
However, this case is a little different
The qx operator doesn't really behave differently -- the array gets concatenated into a string, and that runs. The very fact that we can pass it an array is incidental, and not even documented
We need to pipe input to aspell's STDIN, and shell does that for us simply. We can use a shell with command's LIST form as well, but then we'd need to invoke it explicitly. We can also go for aspell's STDIN by means other than the shell but that's more complex
With a command in a list the command name must be the first word, so that "aspell list" from the question is wrong and it should fail (there is no command named that) ... except that in this case it wouldn't (if the rest were correct), since for qx the array gets collapsed into a string
Finally, apsell nicely exposes its API in a C library and that's been utilized for the module you mention. I'd suggest to install it as a user (no privileges needed) and use that.
You should take a step back and investigate if you can install Text::Aspell without administrator privilige. In most cases that's perfectly possible.
You can install modules into your home directory. If there is no C-compiler available on the server you can install the module on a compatible machine, compile and copy the files.
I am currently working on a project but I have one big problem. I have some picture with a whitespace in the name and I want to do a montage. The problem is that I can't rename my picture and my code is like that :
$pic1 = qq(picture one.png);
$pic2 = qq(picture two.png);
my $cmd = "C:\...\montage.exe $pic1 $pic2 output.png";
system($cmd);
but because of the whitespace montage.exe doesn't work. How can I execute my code without renaming all my pictures?
Thanks a lot for your answer!
You can properly quote the filenames within the string you pass to system, as #Borodin shows in his answer. Something like: system("montage.exe '$pic1' '$pic2'")
However, A more reliable and safer solution is to pass the arguments to montage.exe as extra parameters in the system call:
system('montage.exe', $pic2, $pic2, 'output.png')
Now you don't have to worry about nesting the correct quotes, or worry about files with unexpected characters. Not only is this simpler code, but it avoids malicious injection issues, should those file names ever come from a tainted source. Someone could enter | rm *, but your system call will not remove all your files for you.
Further, in real life, you probably are not going to have a separate scalar variable for each file name. You'll have them in an array. This makes your system call even easier:
system('montage.exe', #filenames, 'output.png')
Not only is that super easy, but it avoids the pitfall of having a command line too long. If your filenames have nice long paths (maybe 50-100 characters), a Windows command line will exceed the max command length after around 100 files. Passing the arguments through system() instead of in one big string avoids that limitation.
Alternatively, you can pass the arguments to montage.exe as a list (instead of concatenating them all into a string):
use strict;
use warnings;
my $pic1 = qq(picture one.png);
my $pic2 = qq(picture two.png);
my #cmd = ("C:\...\montage.exe", $pic1, $pic2, "output.png");
system(#cmd);
You need to put quotes around the file names that have spaces. You also need to escape the backslashes
my $cmd = qq{C:\\...\\montage.exe "$pic1" "$pic2" output.png};
In unix systems, the best approach is the multi-argument form of system because 1) it avoids invoking a shell, and 2) that's the format accepted by the OS call. Neither of those are true in Windows. The OS call to spawn a program expects a command line, and system's attempt to form this command line is sometimes incorrect. The safest approach is to use Win32::ShellQuote.
use Win32::ShellQuote qw( quote_system );
system quote_system("C:\\...\\montage.exe", $pic1, $pic2, "output.png");
I'm trying to automate creating certificates via a Perl script.
The command I want to run is:
easyrsa build-client-full $clientname nopass
The way I thought it should be done in Perl is:
my $arguments = ("build-client-full $clientname nopass");
my $cmd = "$easyrsa_path/easyrsa"." "."$arguments";
system("bash", $cmd);
However, this yields
"file not found"
on execution. I triple checked that the path is correct.
If I try it like this:
my #arguments = ("bash", $easyrsa_path,"build-client-full $clientname nopass");
system(#arguments);
Bash returns
"Unknown command 'build-client-full test nopass'. Run without commands
for usage help."
Background
When you use system(LIST) where LIST has more than one element, Perl will not call the shell, and instead directly invoke the program given by the first element in the LIST, and use the rest of the list as command line arguments to be passed verbatim, with no interpolation by the shell, including no splitting arguments on whitespace.
So in your first example, Perl is running the command bash and passing the string "$easyrsa_path/easyrsa build-client-full $clientname nopass", literally as one big long argument, and in your second example, it's running the command bash and passing the two arguments $easyrsa_path and "build-client-full $clientname nopass". However, I assume that easyrsa needs the three arguments as separate strings in its argument list, which the shell would normally split, but since both of your calls to system aren't using the shell, it's not working.
system (and exec) have four ways of interpreting their arguments, as per the documentation:
If you pass a single string (including a LIST with only one element) that does not contain any shell metacharacters, it is split into words and passed directly to execvp(3) (meaning it bypasses the shell).
Warning: This invocation is easily confused with the following - a single metacharacter will cause the shell to be invoked, which can be dangerous especially when unchecked variables are interpolated into the command string.
If you pass a single string (including a LIST with only one element) that does contain shell metacharacters, the entire argument is passed to the system's command shell for parsing. Normally, that's /bin/sh -c on Unix platforms, but the idea of the "default shell" is problematic, and there is certainly no guarantee that it'll be bash (though it could be).
Warning: In this invocation of system, you have the full power of the shell, which also means you're responsible for correctly quoting and escaping any shell metacharacters and/or whitespace. I recommend you only use this form if you explicitly want the power of the shell, and otherwise, it's usually best to use one of the following two.
If there is more than one argument in LIST, this calls execvp(3) with the arguments in LIST, meaning the shell is avoided.
(See below for caveats on Windows.)
The form system {EXPR} LIST always runs the program named by EXPR and avoids the shell, no matter what's in LIST.
(See below for caveats on Windows.)
The latter two are desirable if you want to pass special characters that the shell would normally interpret, and I'd actually always recommend doing this, since blindly passing user input into system can open up a security hole - I wrote a longer article about that over on PerlMonks.
Solutions
#Borodin and #AnFi have already pointed out: If you simply split up the elements of the LIST properly, it should work - it doesn't look like you need any features of bash or any shell here. And don't forget to check for errors!
system("$easyrsa_path/easyrsa","build-client-full",$clientname,"nopass") == 0
or warn "system failed: \$? = $?";
Note that there are good modules that provide alternatives to system and qx, my go-to module is usually IPC::Run3. These modules are very helpful if you want to capture output from the external command. In this case, IPC::System::Simple might be easier since it provides a drop-in replacement for system with better error handling, as well as systemx which always avoids the shell. (That module is what autodie uses when you say use autodie ':all';.)
use IPC::System::Simple qw/systemx/;
systemx("$easyrsa_path/easyrsa","build-client-full",$clientname,"nopass");
Note that if you really wanted to call bash, you'd need to add the -c option and say system("bash","-c","--","$easyrsa_path/easyrsa build-client-full $clientname nopass"). But as I a said above, I strongly recommend against this, since if $easyrsa_path or $clientname contain any shell metacharacters or malicious content, you may end up having a huge problem.
Windows
Windows is more complicated than the above. The documentation says that the only "reliable" way to avoid calling the shell there is the system PROGRAM LIST form, but on Windows, command line arguments are not passed as a list, but a single big string, and it's up to the called command, not the shell, to interpret that string, and different commands may do that differently - see also. (I have heard good things about Win32::ShellQuote, though.)
Plus, there's the special system(1, #args) form documented in perlport.
If you pass multiple parameters to system then each one forms a separate parameter to the command line. So it is as though you had entered
easyrsa "build-client-full test nopass"
and you correctly get the error
Unknown command 'build-client-full test nopass'
You also don't need to add bash: perl will run the shell for you if necessary
You can either pass the whole command to system
system($cmd)
and perl will pass it to the shell to be processed as if you'd entered it at the command prompt. Or you can split the parameters properly
system("$easyrsa_path/easyrsa", "build-client-full", $clientname, "nopass")
which will make perl call easyrsa directly unless the command contains things that need the shell to process, like output redirection
I'm fairly new to Perl and have been searching the interwebs for documentation for what I'm trying to do. I'm not having any luck.
I have a program that outputs information to stdout with prompts throughout. I need to make a Perl script to pipe that information to a file.
I thought I could use Expect but there seems to be a problem with the pipe after the first prompt.
Here is the part of my code:
# Run program and compare the output to the BASE file
$cmd = "./program arg1 arg2 arg3 arg4 > $outfile";
my $exp = new Expect;
$exp->spawn($cmd);
BAIL_OUT("couldn't create expect object") if (! defined $exp);
$exp->expect(2);
$exp->send("\n");
For this case there is only a single prompt for the user to press "enter". This program is small and very fast - 2 seconds is plenty of time to reach the first prompt.
The output file only contains the first half of the information.
Does anyone have any suggestions on how I can grab the second half as well?
UPDATE:
I've verified that this works with Expect by using a simple script:
spawn ./program arg1 arg2 arg3 arg4
expect "<Return>"
send "\r"
interact
Where "< Return >" is a verbose expression that the Perl script could look for.
Note: I've tried writing my Perl script to expect "< Return >"...it makes no difference.
i.e.
$exp->expect(2, '-re', "<Return>")
Any thoughts?
UPDATE2:
Hazaah! I've found a solution to my problem...completely by accident.
So, I had a mistype in some test code I made...
$exp->expect(2);
$exp->send("\r");
$exp->expect(2);
Note the trailing expect(2)...I accidentally left that in and it worked!
So, I'm trying to understand what is happening. Unix expect does not seem work this way! It appears Expect implemented in Perl "expects" anything...not just prompts?
So, I provided expect another 2 seconds to collect stdout and I am able to get everything.
If anyone can offer some more detailed information as to what is going on here I'd love to understand what is going on.
Try sending \r instead of \n - you're trying to emulate a carriage return, not a newline, and the tty settings might not be translating them.
ALSO:
A suggestion from the Expect docs FAQ section, which seems likely given your accidental solution:
My script fails from time to time without any obvious reason. It
seems that I am sometimes loosing output from the spawned program.
You could be exiting too fast without giving the spawned program
enough time to finish. Try adding $exp->soft_close() to terminate the
program gracefully or do an expect() for 'eof'.
Alternatively, try adding a 'sleep 1' after you spawn() the program.
It could be that pty creation on your system is just slow (but this is
rather improbable if you are using the latest IO-Tty).
Standard unix/tcl expect doesn't exit in interactive mode, which could give your program enough time to finish running.
It's been a while since I've used Expect, but I'm pretty sure you need to provide something for Expect to match the prompt against:
$exp->expect( 2, 'Press enter' );
for example.
I am trying to create my first zsh completion script, in this case for the command netcfg.
Lame as it may sound I have stuck on the first hurdle, disclaimer, I know how to do this crudely, however I seek the "ZSH WAY" to do this.
I need to list the files in /etc/networking but only the files, not the directory component, so I do the following.
echo $(ls /etc/network.d/*(.))
/etc/network.d/ethernet-dhcp /etc/network.d/wireless-wpa-config
What I wanted was:
ethernet-dhcp wireless-wpa-config
So I try (excuse my naivity) :
echo ${(s/*\/)$(ls /etc/network.d/*(.))}
/etc/network.d/ethernet-dhcp /etc/network.d/wireless-wpa-config
It seems that this doesn't work, I'm sure there must be some clever way of doing this by splitting into an array and getting the last part but as I say, I'm complete noob at this.
Any advice gratefully received.
General note: There is no need to use ls to generate the filenames. You might as well use echo some*glob. But if you want to protect the possible embedded newline characters even that is a bad idea. The first example below globs directly into an array to protect embedded newlines. The second one uses printf to generate NUL terminated data to accomplish the same thing without using a variable.
It is easy to do if you are willing to use a variable:
typeset -a entries
entries=(/etc/network.d/*(.)) # generate the list
echo ${entries#/etc/network.d/} # strip the prefix from each one
You can also do it without a variable, but the extra stuff to isolate individual entries is a bit ugly:
# From the inside, to the outside:
# * glob the entries
# * NUL terminate them into a single string
# * split at NUL
# * strip the prefix from each one
echo ${${(0)"$(printf '%s\0' /etc/network.d/*(.))"}#/etc/network.d/}
Or, if you are going to use a subshell anyway (i.e. the command substitution in the previous example), just cd to the directory so it is not part of the glob expansion (plus, you do not have to repeat the directory name):
echo ${(0)"$(cd /etc/network.d && printf '%s\0' *(.))"}
Chris Johnsen's answer is full of useful information about zsh, however it doesn't mention the much simpler solution that works in this particular case:
echo /etc/network.d/*(:t)
This is using the t history modifier as a glob qualifier.
Thanks for your suggestions guys, having done yet more reading of ZSH and coming back to the problem a couple of days later, I think I've got a very terse solution which I would like to share for your benefit.
echo ${$(print /etc/network.d/*(.)):t}
I'm used to seeing basename(1) stripping off directory components; also, you can use echo /etc/network/* to get the file listing without running the external ls program. (Running external programs can slow down completion more than you'd like; I didn't find a zsh-builtin for basename, but that doesn't mean that there isn't one.)
Here's something I hope will help:
haig% for f in /etc/network/* ; do basename $f ; done
if-down.d
if-post-down.d
if-pre-up.d
if-up.d
interfaces