two shell script questions

tutwabee · 08-09-2004, 03:00 PM

I am making a script which uses mplayer/mencoder to rip a dvd, crop it, combine two mpegs from seperate disks if necessary, and convert to an avi if necessary. At the moment I have a perl script that does the file combining and I can't find a way to make a shell script that grabs the crop value from the command 'mplayer -ao null -vo xv -vop cropdetect [filename]'

1: Does anyone know how I can use shell to combine two files?
2: Does anyone know how I can get the crop value from the cropdetect output?

The current perl script I am using to combine the files is:

Quote:

#!/usr/bin/perl

# open FIRSTFILE, "1.mpeg";
# @firstfile = <FIRSTFILE>;
# close FIRSTFILE;

open SECONDFILE, "2.mpeg";
@secondfile = <SECONDFILE>;
close SECONDFILE;

open FULLFILE, ">>full.mpeg";
# foreach $line (@firstfile) {
# print FULLFILE $line;
# }

foreach $line (@secondfile) {
print FULLFILE $line;
}

close FULLFILE;

JZL240I-U · 08-10-2004, 05:39 AM

Look at this http://www.tldp.org/guides.html#abs

bulliver · 08-10-2004, 02:38 PM

1: By using the concatanate (cat) command of course. Here's an example:

Code:

me@mine]$ echo "aaaaaaaaaaaaaaa" > a.txt
me@mine]$ echo "bbbbbbbbbbbbbbb" > b.txt
me@mine]$ cat a.txt b.txt
aaaaaaaaaaaaaaa
bbbbbbbbbbbbbbb
me@mine]$ cat a.txt b.txt > c.txt
me@mine]$ cat c.txt
aaaaaaaaaaaaaaa
bbbbbbbbbbbbbbb
me@mine]$

The formula is "cat file1 file2 > file3"
So: "cat 1.mpeg 2.mpeg > 3.mpeg"

2. output redirection is accomplished using the backtick operator:

Code:

me@mine]$ FOO=`uptime`
me@mine]$ echo $Foo
12:36:36 up 18:43,  1 user,  load average: 0.04, 0.05, 0.00
me@mine]$

So: FOO=`mplayer -ao null -vo xv -vop cropdetect [filename]`

tutwabee · 08-10-2004, 02:45 PM

Thank you bulliver. I hadn't thought of using the cat command in that way before.

bulliver · 08-10-2004, 06:03 PM

No problem. The only thing I am not sure of is if it will work on binary files (ie: video clips). Perhaps it only works on text files?

EDIT: I just tried it on a couple of mp3 files and it worked flawlessly using cat.