Specifying a variable without editing my script everytime

(1 of Several very recent, semi-related posts in a series to record/watch tv)

Hi, I haven't really liked any of the applications I've found for recording tv with linux, either they don't have options I desire, they are too slow, they require specific applications I do not wish to use or just something I don't like about em... So I am trying to eventually be able to just open up a terminal and type something like:
mentv 16
and have a script I've created called mentv start recording channel 16 (using mencoder) until I hit ctrl+c

Here is the script (no, I am not kidding, I just don't know scripting that well, or rather, at all )

#!/bin/bash
mencoder -tv on:chanlist=us-cable:channel=16:channels=13-Fox,11-UPN,16-WB,8-Disc:driver=v4l:width=720:height=480:norm=ntsc:forceaudio:amode=1:adevice=/dev/dsp \
-ovc lavc -lavcopts vcodec=mpeg4:vhq:vbitrate=1100 \
-oac mp3lame -lameopts cbr:br=128 -vop scale=512:340,pp=tn/lb -sws 1 \
-o output.avi

And so I'd like to somehow make:
channel=16
be a variable that recieves it's input from me after running the script, as shown above with:
$mentv 12
to record channel 12.

I haven't even the slightest idea of where to start, so if anyone has any ideas I'd greatly appreciate it.

Thanks

Does the following meet your requires?

#!/bin/bash

echo "Command line arg 1 = $1"
echo "Command line arg 2 = $2"

Which gave me

root@tetsuo:~# ./test.sh record 16
Command line arg 1 = record
Command line arg 2 = 16

HTH

Jamie...

tar clfpv - $1 |(cd /$2; tar xpf - --same-owner --atime-preserve)

this is a stupid file copying script i use.
i named it tarcopy. it takes 2 variables from the
command line. source and destination

tarcopy . /work/stuff/

. gets assigned to $1
/work/stuff/ gets assigned to $2

How about using "getopts" using "-c <channel>":

#!/bin/bash
while getopts hc: OPT; do case "$OPT" in
c) channel="$OPTARG"; printf "You choose channel $OPTARG\n";;
h) printf "%sUsage: $0 -c <channel>.\n"; exit 1;; esac; done;
case "${#channel}" in 0) exit 1;; esac

mencoder -tv on:chanlist=us-cable:channel=${channel}\
etc etc.

nb. channels= and channel= vairables are not compatible with each other afaik.

Originally posted by jharris Does the following meet your requires? #!/bin/bash echo "Command line arg 1 = $1" echo "Command line arg 2 = $2" Which gave me root@tetsuo:~# ./test.sh record 16 Command line arg 1 = record Command line arg 2 = 16 HTH Jamie...

Woohoo! Thanks, I just tried a straight forward $1, so now it looks like like this:

mencoder -tv on:chanlist=us-cable:channel=$1:driver=v4l....

And it works
mentv 13, now records from channel 13 for me, mentv 14 from 14 and so on..

Thank you for the suggestion!

[Originally posted by UnSpawn How about using "getopts" using "-c <channel>": #!/bin/bash while getopts hc: OPT; do case "$OPT" in c) channel="$OPTARG"; printf "You choose channel $OPTARG\n";; h) printf "%sUsage: $0 -c <channel>.\n"; exit 1;; esac; done; case "${#channel}" in 0) exit 1;; esac mencoder -tv on:chanlist=us-cable:channel=${channel}\ etc etc.

I decided to give this a try as well, just to see what the outcome would be like, however I don't know if I compiled getopts correctly, or what the problem was, but I would just get returned to the prompt with no error. I compiled getopts by:
gcc main.c getopts.c -o getopts
And then copied the a.out (renamed getopts from -o getopts) to /usr/local/bin
Thank you anyway for your suggestion it intreagued me very much, helped me learn a few things about compiling along the way!

Originally posted by acid_kewpie nb. channels= and channel= vairables are not compatible with each other afaik.

Thank you for that as well, that must have been my error since it's working great now.



Cool

]$ type getopts
getopts is a shell builtin

Execute "sh -x <scriptname> -c 16" and you'll see what it should look like.