How do I make a script accept wildcards in arguments?

CartersAdvocate · 12-11-2008, 01:13 PM

I have a script that I pass a username to, and it converts an avi file into a format that my PS3 can read. As of right now, I have to run ./avi2ps3 filename.avi

I was wondering how to get it to accept wildcards such as ./avi2ps3 file*.avi or ./avi2ps3 ./*

Also, if I run ./avi2ps3 filename.avi filename2.avi would that work?

Here is the one line script as it stands right now:

Code:

sudo ffmpeg -i `basename "$1" .avi`.avi -s 640x352 -vcodec libxvid -b 1037k -acodec libmp3lame -ab 96k `basename "$1" .avi`-new.avi && rm "$1" && mv `basename "$1" .avi`-new.avi "$1"

Feel free to suggest any other improvements to it as well.

Thanks,
Jeff

H_TeXMeX_H · 12-11-2008, 01:24 PM

Well, you could do something like:

Code:

for i in "$1"
do
    ffmpeg -i `basename "$i" .avi`.avi -s 640x352 -vcodec libxvid -b 1037k -acodec libmp3lame -ab 96k `basename "$i" .avi`-new.avi && rm "$i" && mv `basename "$i" .avi`-new.avi "$i"
done

CartersAdvocate · 12-11-2008, 01:27 PM

That would work for both all of my examples?

./avi2ps3 file*.avi
./avi2ps3 ./*
./avi2ps3 filename1.avi filename2.avi

saulgoode · 12-11-2008, 01:32 PM

Before your script is invoked, all of the filenames are expanded into a list (separated with spaces by default). This list of filenames is accessible from within your script with the positional parameters $1, $2, $3, et cetera; OR in its entirety with $* .

The following example should demonstrate how this can be used in your script:

Code:

for f in $* ; do echo $f ; done

If you need to pass parameters to your script which are not filenames (switches, for example) then your script will need to process those properly (a task for which the BASH built-in 'shift' command is most helpful). I would recommend examining Slackware's package management scripts (e.g., /sbin/installpkg) for examples of handling more complicated situations.

CartersAdvocate · 12-11-2008, 01:34 PM

I only need to pass filenames, so that should work. Thanks for the help

H_TeXMeX_H · 12-11-2008, 01:36 PM

Quote:

Originally Posted by j3ff3r

That would work for both all of my examples?

./avi2ps3 file*.avi
./avi2ps3 ./*
./avi2ps3 filename1.avi filename2.avi

It would only handle the first two, I think. But the third one is not much use, because you can just do:

Code:

./avi2ps3 filename*.avi

Disillusionist · 12-11-2008, 01:38 PM

If you have files with spaces in their names, you will get errors.

Alternative:

Code:

#!/bin/bash
ls $1|while read l_file
do
   if [ -f "$l_file" ]
   then
      sudo ffmpeg -i `basename "$l_file" .avi`.avi -s 640x352 -vcodec libxvid -b 1037k -acodec libmp3lame -ab 96k `basename "$l_file" .avi`-new.avi && rm "$l_file" && mv `basename "$l_file" .avi`-new.avi "$l_file"
   fi
done

Additionally, if you pass * without the .avi extension, you will pick up files that you probably don't want to process, therefore you might want to change the file test to:

if [ -f "`basename "$l_file" .avi`.avi" ]

CartersAdvocate · 12-11-2008, 01:47 PM

Edit: Deleted after reading other responses...ignore this one

CartersAdvocate · 12-11-2008, 02:01 PM

Ok, how's this one?

Code:

#!/bin/bash
ls $*|while read l_file
do
   if [ -f "`basename "$l_file" .avi`.avi" ]
   then
      sudo ffmpeg -i `basename "$l_file" .avi`.avi -s 640x352 -vcodec libxvid -b 1037k -acodec libmp3lame -ab 96k `basename "$l_file" .avi`-new.avi && rm "$l_file" && mv `basename "$l_file" .avi`-new.avi "$l_file"
   fi
done

Disillusionist · 12-11-2008, 02:31 PM

That should work for the specified examples, however it should be noted that:

If you do not specify a parameter, it will process all files in the current working directory.
It will not work when specifying files in a different directory.

You may want to have a look at dirname to enhance the script further:

if [ -f "`dirname "$l_file"`/`basename "$l_file" .avi`.avi" ]

CartersAdvocate · 12-11-2008, 02:39 PM

Ahh, I was using basename to strip off the extension, I didn't realize it stripped off the path also...I'll look into adding dirname to it...that shouldn't be too hard

CartersAdvocate · 12-11-2008, 02:40 PM

Oh, and if I just add an

Code:

if $*

clause to it, that would fix the problem of not specifying a paramater, right? (sorry, I'm a bash scripting newb)

Disillusionist · 12-11-2008, 02:44 PM

To make life easier just run dirname and basename once:

Code:

#!/bin/bash
ls $*|while read l_file
do
   l_basefile="`dirname "$l_file"`/`basename "$l_file" .avi`"

   if [ -f "${l_basefile}.avi" ]
   then
      sudo ffmpeg -i "${l_basefile}.avi" -s 640x352 -vcodec libxvid -b 1037k -acodec libmp3lame -ab 96k "${l_basefile}-new.avi" && rm "${l_basefile}" && mv "${l_basefile}-new.avi" "${l_basefile}"
   fi
done

CartersAdvocate · 12-11-2008, 02:46 PM

Cool, thanks

Disillusionist · 12-11-2008, 02:46 PM

Quote:

Originally Posted by j3ff3r

Oh, and if I just add an

Code:

if $*

clause to it, that would fix the problem of not specifying a paramater, right? (sorry, I'm a bash scripting newb)

You could test the number of parameters passed:

Code:

if [ $# -eq 0 ]
then
   echo "You didn't enter a parameter!"
   exit 1
fi