Rails not responding to ffmpeg commands - ruby-on-rails

I am trying to run this command here:
f = open("|ffmpeg -i /Users/joaoh82/Desktop/teste.MP4")
result = f.read()
But I am not getting any response...
But when I try this command in the terminal it works great:
ffmpeg -i /Users/joaoh82/Desktop/teste.MP4
But now on rails code. Funny thing is that when I try the same thing with some else like an echo $PATH it works great! Like:
f = open("|echo $PATH")
result = f.read()
Any ideas!?

ffmpeg -i prints to stderr, which won't be captured by your pipe. You could redirect stderr to stdout:
result = `ffmpeg -i /Users/joaoh82/Desktop/teste.MP4 2>&1`

You probably need to specify the full path to ffmpeg. It might be working in your shell because ffmpeg is in your PATH.
Basically in your shell, type which ffmpeg. Use that full path in your open() call.

Related

Why QProcess is not showing stdout from bash script executed in remote server?

I made an script (findx.h) that doesn't have any problem when i ran it on Solaris server via console (bash-3.2$ ./findx.sh)
The problem appears when i try to run it from a windows Qt app using QProcess (code below) where it doesn't display the ouput of the command.
I tried little variations and appear to show data when just use one pipe instead of two. But i need the two: grep and ggrep.
//findx.h in solaris
//WHAT WORKS
#!/bin/bash
echo pass | sudo -S /usr/sbin/snoop -x0 -ta HSM1000 port 1000
//WHAT I WANT
#!/bin/bash
echo pass | sudo -S /usr/sbin/snoop -x0 -ta HSM1000 port 1000 | /usr/sfw/bin/ggrep -A 2 KR01
//Qt on windows
QString commands="(";
commands +="source setpath.sh";
commands +=";/path/to/script/findx.sh";
commands +=")";
this->logged=false;
QString program = "plink.exe";
QStringList arguments;
arguments <<"-ssh"
<<ip
<<"-l"
<<user
<<"-pw"
<<pass
<<commands;
this->myProcess=new QProcess(this);
connect(this->myProcess,SIGNAL(started()),
this, SLOT(onprocess_started()));
connect(this->myProcess, SIGNAL(errorOccurred(QProcess::ProcessError)),
this, SLOT(onprocess_errorOcurred(QProcess::ProcessError)));
connect(this->myProcess, SIGNAL(finished(int, QProcess::ExitStatus)),
this, SLOT(onprocess_finished(int, QProcess::ExitStatus)));
connect(this->myProcess, SIGNAL(readyReadStandardError()),
this, SLOT(onprocess_readyReadStandardError()));
connect(this->myProcess, SIGNAL(readyReadStandardOutput()),
this, SLOT(onprocess_readyReadStandardOutput()));
connect(this->myProcess, SIGNAL(stateChanged(QProcess::ProcessState)),
this, SLOT(onprocess_stateChanged(QProcess::ProcessState)));
this->myProcess->start(program, arguments);
this->ui->labStatus->setText("Starting");
return 0;
// How i read, i do the same for stderr and put it also in plainOutput
QByteArray err=this->myProcess->readAllStandardOutput();
QString m="Standard output:"+QString(err.data());
this->ui->plainOutput->appendPlainText(m);
please any advice would be useful.
Thanks in advance.

Formatting nmap output

I have an nmap output looking like this
Nmap scan report for 10.90.108.82
Host is up (0.16s latency).
PORT STATE SERVICE
80/tcp open http
|_http-title: Did not follow redirect to https://10.90.108.82/view/login.html
I would like the output to be like
10.90.108.82 http-title: Did not follow redirect to https://10.90.108.82/view/login.html
How can it be done using grep or any other means?
You can use the following nmap.sh script like that:
<nmap_command> | ./nmap.sh
nmap.sh:
#!/usr/bin/env sh
var="$(cat /dev/stdin)"
file=$(mktemp)
echo "$var" > "$file"
ip_address=$(head -1 "$file" | rev | cut -d ' ' -f1 | rev)
last_line=$(tail -1 "$file" | sed -E "s,^\|_, ,")
printf "%s%s\n" "$ip_address" "$last_line"
rm "$file"
If you do not mind using a programming language, check out this code snippet with Python:
import nmapthon as nm
scanner = nm.NmapScanner('10.90.108.82', ports=[80], arguments='-sS -sV --script http-title')
scanner.run()
if '10.90.108.82' in scanner.scanned_hosts(): # Check if host responded
serv = scanner.service('10.90.108.82', 'tcp', 80)
if serv is not None: # Check if service was identified
print(serv['http-title'])
Do not forget to execute pip3 install nmapthon.
I am the author of the library, feel free to have a look here
Looks like you want an [nmap scan] output to be edited and displayed as you wish. Try bash scripting, code a bash script and run it.
Here's an link to a video where you might find an answer to your problem:
https://youtu.be/lZAoFs75_cs
Watch the video from the Time Stamp 1:27:17 where the creator briefly describes how to cut-short an output and display it as we wish.
If you require, I could code an bash script to execute an cut-shorted version of the output given by an nmap scan.

Lua: forward output from Minicom

I have a Lua script and in there I open a minicom session which executes a script (with the -S" parameter).
local myFile = assert(io.popen('minicom -S myScript.sh ' myDevice ' -C myLogFile.log'))
local myFileOutput = myFile:read('*all')
myFile:close()
This works really fine.
But I would like to get the same output as if I execute the minicom command itself:
minicom -S myScript.sh ' myDevice ' -C myLogFile.log
Right now I don't get any output at all (I know that that's somehow obvious).
I would that the output should also occur at (at least nearly) the same time as with the minicom command itself. Not one big chuck of data at the end.
Does anyone know how to achieve that?
If I understand you correctly, you need something like
local myFile = assert(io.popen('minicom ...'))
for line in myFile:lines('l') do
print(line)
end
myFile:close()

error while executing lua script for redis server

I was following this simple tutorial to try out a simple lua script
http://www.redisgreen.net/blog/2013/03/18/intro-to-lua-for-redis-programmers/
I created a simple hello.lua file with these lines
local msg = "Hello, world!"
return msg
And i tried running simple command
EVAL "$(cat /Users/rsingh/Downloads/hello.lua)" 0
And i am getting this error
(error) ERR Error compiling script (new function): user_script:1: unexpected symbol near '$'
I can't find what is wrong here and i haven't been able to find someone who has come across this.
Any help would be deeply appreciated.
Your problem comes from the fact you are executing this command from an interactive Redis session:
$ redis-cli
127.0.0.1:6379> EVAL "$(cat /path/to/hello.lua)" 0
(error) ERR Error compiling script (new function): user_script:1: unexpected symbol near '$'
Within such a session you cannot use common command-line tools like cat et al. (here cat is used as a convenient way to get the content of your script in-place). In other words: you send "$(cat /path/to/hello.lua)" as a plain string to Redis, which is not Lua code (of course), and Redis complains.
To execute this sample you must stay in the shell:
$ redis-cli EVAL "$(cat /path/to/hello.lua)" 0
"Hello, world!"
If you are coming from windows and trying to run a lua script you should use this format:
redis-cli --eval script.lua
Run this from the folder where your script is located and it will load a multi line file and execute it.
On the off chance that anyone's come to this from Windows instead, I found I had to do a lot of juggling to achieve the same effect. I had to do this:
echo “local msg = 'Hello, world!'; return msg” > hello.lua
for /F "delims=" %i in ('type hello.lua') do #set cmd=%i
redis-cli eval "%cmd%" 0
.. if you want it saved as a file, although you'll have to have all the content on one line. If you don’t just roll the content into a set command
set cmd=“local msg = 'Hello, world!'; return msg”
redis-cli eval "%cmd%" 0

How to capture ffmpeg output in rails?

I'm running a ffmpeg command to try to get the duration of a video file, the command is as follows...
system('ffmpeg -i C:\Users\example\Desktop\video9.mp4 -f ffmetadata')
When I run that line it outputs a lot of info to the rails console, including duration. But how would I capture that info so I can split it and grab the data I need? (I'm doing this inside a rails controller)
When I run something like this...
metadata = system('ffmpeg -i C:\Users\example\Desktop\video9.mp4 -f ffmetadata')
puts metadata
All it returns is false.
Use:
output = `ffmpeg -i C:\\Users\\example\\Desktop\\video9.mp4 -f ffmetadata`
The problem is that system doesn't capture the output of the command being run. Instead, we use %x[...] or its equivalent using backticks, which captures the sub-shell's STDOUT.
If you need more control, look at Open3.capture3.
Found it...
inspect_command = "ffmpeg -i " + file_location + " 2>&1 "
metadata = `#{inspect_command}`
If all you need to get is the video duration use ffprobe instead of ffmpeg. It returns the video metadata directly.

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