Help with Bash scripts
 

Hello all,

I have written a bash script which counts the number of lines in a given text file, and then chooses a random number and then reads the line number from the file basis that random number. The script looks like this:

Lets say the content of each line in myfile was a bunch of parameters or options for Xine. And lets say that I want my script to launch Xine using the contents of the line that was read by sed. How would I finally use xine in my script?

I tried adding as the last line in my script :

But xine is not accepting the parameters.

HOWEVER, If I echo first:

then I can copy and paste the line that was echoed into the terminal window and Xine executes properly using the correct switches.

I really hope someone can help.

Hmmm, doesn't seem to work.

It causes Xine to throw up an error box saying it cannot find the MRL.

Plus, I don't quite understand all of what you have presented there.

See http://www.linuxquestions.org/questi...l.....-309312/ for a similar problem. Basically it is possible that the MRL's that are being read in are not valid or they are no full pathnames.

Linux Archive

Yes but, if I use:

then I can copy and paste the line that was echoed into the terminal window and Xine executes properly using the correct switches.

So the MRL is valid, I just don't know how to make a BASH script launch xine and pass a bunch of parameters that are stored in a $variable.

An example of the parameters would be:

--enqueue -S session=0,mrl=/home/user/kelly.mpg#volume:100

Now if I was to type into a terminal console:

xine --enqueue -S session=0,mrl=/home/user/kelly.mpg#volume:100

it would work.

I also know that when I run my BASH script, $LINE actually does look like: --enqueue -S session=0,mrl=/home/user/kelly.mpg#volume:100

but for some reason, if I try to use:

xine ${LINE}

The contents of $LINE are not treated as one bunch of parameters. I have a funny feeling that xine is trying to treat $LINE as just an MRL, which $LINE is more than just an MRL.


I have also tried (with $LINE = /home/user/kelly.mpg#volume:100 (hence, just the valid url with a volume setting on the end which is allowed when using the enqueue option)

xine --enqueue -S session=0,mrl=${LINE}

Works. I'm not a bash-scripter so what do the curlies do?

Hi,

What happens if you try the following from the command line:
If that doesn't work, try adding a set -x between the echo and xine statement, that should show you what bash does and how xine is executed.

I've discovered that:

will work, so long as the line from the file looked like this:

/home/user/kelly.mpg

which is kind of nearly what I want, only that:

the line from the file MUST have a volume specifier at the end, so the line from the file has to look like this:

/home/user/kelly.mpg#volume:10

So my next question would be, if I use sed to get read the line and print the line to $LINE. How could I strip the #volume:10 from it and make $VOL = #Volume:10 ?

Gosh I hope this has made sense to someone, coz its difficult to describe.

Another thing that came to mind (not a reply to post #8):

Have you tried the eval command?

eval xine ${LINE}

Well, that throws some light onto whats going wrong (I could see that #volume:10 was being treated as part of the MRL and also adding a ' to where ever there was a space in a file name). Soooo, basically if I use:

xine "$LINE" seems to work with everything including file names that have spaces, so long as I dont have the #volume:10 on the end of the line.

However, I need the volume argument on the end of the line, and I need to pass that as an arg to xine (some files are louder than others you see). So if I can just know how to separate the two pieces of information into two separate variables, I think it might do the trick.

So close to what I need, I can smell it.

Hi,

The # in the options line could be (is??) seen by bash as special when using ${LINE} (man bash for the details). That is why $LINE works (more or less) and ${LINE} does not.

Maybe my eval option helps......

Yeah cool, I also think that if I read a line from a file that looks like this:

/home/user/kelly.mpg#volume:100

and if I can use sed to put the above line into a variable called $TEMP

and then somehow split $TEMP into two pieces, so that:

$LINE = /home/user/kelly.mpg

and introduce a new variable for volume, so that:

$VOL = #volume:10

I reckon I can make that work by doing:

xine --enqueue "$LINE"$VOL

Hi,

Did you yake a look at post #9?

You don't have to cut the original $LINE into pieces if that works.....

Hi,

If the line in the file looks like this:

/home/user/kelly.mpg#volume:100

Using either ${LINE} or $LINE behaves the same.

It seems the #volume:100 really needs to be cut from the $LINE and put into another variable like $VOL.


I just tested:

and it worked like a dream.

So now I need to learn how to cut the line into two pieces.


Edit: Oh wait, eval may work....one sec.

It is still not clear from your answer if you tried the eval command ;)

Also try ${LINE}.