Shell Programming and Scripting

I have the following block from a script (it's not the entire script, but I'm confident it's all that is pertinent)

Code:

echo "$SESSIONS"|while read ID;do
ASSETID=$(echo "$ERRORS"|grep -i "$ID"|grep FX_Media_Session_Playlist::init_playlist|grep -i asset_id=|awk '{print $11}')
BLADE=$(echo "$ERRORS"|grep -i "$ID"|grep FX_Media_Session_Playlist::init_playlist|grep -i asset_id=|awk '{print $1}'|tr -d ":")
#psh $BLADE "grep "$ASSETID" /opt/VideoServer/logs/streamer_log.txt|head -1|awk '{print $8}'"
echo "$ASSETID is on $BLADE"
done

which returns:

Code:

[root@xcat01 utils]# ./xxx -y
asset_id=269939 is on p2b023
asset_id=269944 is on p1b007
asset_id=269314 is on p1b008
asset_id=266224 is on p1b006
asset_id=264377 is on p2b006
asset_id=265144 is on p1b008
asset_id=269455 is on p2b020

However, when I uncomment the shh command and comment out the echo command, it only goes through the first asset ID in the loop, and then exits out of the script.

Code:

[root@xcat01 utils]# ./xxx -y
p2b023: 06/05/10 11:59:55.847   I S10.250.18.185         STREAMER         0  AGABAAAALHEHKAME  FX_Live_Asset_Ingestion_Allocate_Service::make_reply Id=AGABAAAALHEHKAME asset_id=269939
[root@xcat01 utils]#

I've tried wrapping the SSH in every combination of single quotes and double quotes I can think of, and it always does just the first value from the loop and then exits. I'm stumped.

Note: it says psh, but that's because this is being done from an xcat machine. It should work exactly the same as ssh, and in an attempt to debug, I tried using ssh, and it was the same problem.

Note2: In the final version, the ssh command will be in a variable, and I'll be awking out a column of what it retuns (SESSIONID=$(ssh blade grep yadda yadda|awk '{print $9}'). I don't know if that matters.

First, format your code so that it is more easily readable:

Code:

echo "$SESSIONS" |
 while read ID;do
   ASSETID=$(
     echo "$ERRORS" |
     grep -i "$ID"  |
     grep FX_Media_Session_Playlist::init_playlist |
     grep -i asset_id= |
     awk '{print $11}'
     )

   BLADE=$(
     echo "$ERRORS" |
     grep -i "$ID" |
     grep FX_Media_Session_Playlist::init_playlist |
     grep -i asset_id= |
     awk '{print $1}'|tr -d ":"
     )

   #psh $BLADE "grep "$ASSETID" /opt/VideoServer/logs/streamer_log.txt | head -1 | awk '{print $8}'"
   echo "$ASSETID is on $BLADE"
 done

Then quote variable references:

Code:

psh "$BLADE" "grep $ASSETID /opt/VideoServer/logs/streamer_log.txt | head -1 | awk '{print $8}'"

You have 6 calls to grep and two to awk for every iteration of the loop. It would probably be more efficient to process the input before entering the loop, but you haven't supplied the contents of $SESSIONS, so it may not be.

It shouldn't in this case (because there's a command), but ssh normally reads from the standard input, so it would read the entire output of "echo".

If the problem persists after fixing the quoting, try adding the -n option to ssh.

That could make quoting even more problematic, unless it is only the command itself in the variable and not the arguments.

Apologies for the formatting. I've been wrestling with this for a while. I assure you the actual production copy will be properly formatted, but this was me wiping everything out and going back through and adding one line at a time, trying to find the point of failure.


I'm not sure what you mean by quote your variable references. I thought that I had, but it's possible that I may have missed something.

I'm aware of (and loathe) the number of external processes that are being called by this, but at the moment I'm more concerned with completing the logic of what I'm trying to do than with optimization. I hate sloppy scripting, but in this case I'm working on a deadline, and honestly, for the amount of info processed vs the power of the machine I'm working with...it's a secondary concern (but my OCD won't let me leave it if I can find a better way). I just didn't want to waste the boards time with cleanup...I can do that. Or at least try and come back.

Someone else has mentioned the -n option and I think it's worth a shot. I've already left the office, so I'll have to give it a try in the moring.

I'm hoping it won't be an issue. As I said, the variable should just be value=$(ssh yadda|yadda) but I suppose I'll see in the morning.

Thanks for all your input though. Much appreciated.