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Full Discussion: Bash loops and variable scope
Top Forums UNIX for Dummies Questions & Answers Bash loops and variable scope Post 302503696 by 1skydive on Friday 11th of March 2011 02:01:22 PM
Old 03-11-2011
Bash loops and variable scope
Hi All,

I've been researching this problem and I am pretty sure that the issue is related to the while loop and the piping. There are plenty of other threads about this issue that recommend removing the pipe and using redirection. However, I haven't been able to get it working using the ssh and grep command.

Code:
#!/bin/bash
export date=`date '+%m/%d/%Y'`
ALERT=90
ADMIN=me@me.com
DIR="/tmp"
COUNT=0

function type1(){

  local host=$1
  ssh $host df -hP --exclude-type=nfs | grep -E "sd[bcd]|mapper" | grep -v VGsys | awk "{print \$5 \" \" \$1}" | while read output;
  do
    usep=$(echo $output | awk "{ print \$1}" | cut -d'%' -f1  )
    partition=$(echo $output | awk "{ print \$2 }" )
    if [ "$usep" -ge "$ALERT" ]; then
      USAGE=$(echo -e "$partition ($usep%)")
      TOTAL="$TOTAL $USAGE"
      echo $TOTAL
    fi
  done
  echo $TOTAL
  echo -e "$host\n$TOTAL\n"  >> "$DIR/servers.txt"

}

for i in server1 server2 server2; do
  type1 $i;
done


mail -s "$ALERT% Storage Report for $date" $ADMIN  < "$DIR/servers.txt"

rm "$DIR/server.txt"

As you can see, the TOTAL is available within the while loop but is then empty after the loop exits.

Any suggestions appreciated.

Thanks for you help.

---------- Post updated at 02:01 PM ---------- Previous update was at 10:35 AM ----------

Hah! So why is it, you bash (no pun intended) your head against a wall for a couple of days, trying every possible combination you can think of. No sooner you post the question, the light bulb goes off.

So, I moved the ssh command to the for loop output to a file and then used redirection for the while loop. Its not perfect, but at least I have my variables now and can work on the other issues I have.

This is what I ended up doing:

Code:
#!/bin/bash
export date=`date '+%m/%d/%Y'`
ALERT=90
ADMIN=me@me.com
DIR="/tmp"
COUNT=0

function type1(){

  local host=$1
  while read output
  do
    usep=$(echo $output | awk "{ print \$1}" | cut -d'%' -f1  )
    partition=$(echo $output | awk "{ print \$2 }" )
    if [ "$usep" -ge "$ALERT" ]; then
      USAGE=$(echo -e "$partition ($usep%)")
      TOTAL="$TOTAL$USAGE"
      echo $TOTAL
    fi
  done < "$DIR/hosts.txt"
  echo -e "$host\n$TOTAL\n"  >> "$DIR/servers.txt"

}

for i in server1 server2 server2; do
  ssh $host df -hP --exclude-type=nfs | grep -E "sd[bcd]|mapper" | grep -v VGsys | awk "{print \$5 \" \" \$1}" >> "$DIR/hosts.txt"
  type1 $i;
done


mail -s "$ALERT% Storage Report for $date" $ADMIN  < "$DIR/servers.txt"

rm "$DIR/server.txt"
rm "$DIR/hosts.txt"

Hope it helps someone else out.
 

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