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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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LEARN ABOUT REDHAT

unix2dos

unix2dos(1)						      General Commands Manual						       unix2dos(1)

NAME

       unix2dos - UNIX to DOS text file format converter

SYNOPSYS

       unix2dos [options] [-c convmode] [-o file ...] [-n infile outfile ...]

       Options:

       [-hkqV] [--help] [--keepdate] [--quiet] [--version]

DESCRIPTION

       This manual page documents unix2dos, the program that converts text files in UNIX format to DOS format.

OPTIONS

       The following options are available:

       -h --help
	      Print online help.

       -k --keepdate
	      Keep the date stamp of output file same as input file.

       -q --quiet
	      Quiet mode. Suppress all warning and messages.

       -V --version
	      Prints version information.

       -c --convmode convmode
	      Sets conversion mode. Simulates unix2dos under SunOS.

       -o --oldfile file ...
	      Old file mode. Convert the file and write output to it. The program default to run in this mode. Wildcard names may be used.

       -n --newfile infile outfile ...
	      New  file  mode.	Convert the infile and write output to outfile. File names must be given in pairs and wildcard names should NOT be
	      used or you WILL lost your files.

EXAMPLES

       Get input from stdin and write output to stdout.

	      unix2dos

       Convert and replace a.txt. Convert and replace b.txt.

	      unix2dos a.txt b.txt

	      unix2dos -o a.txt b.txt

       Convert and replace a.txt in ASCII conversion mode.  Convert and replace b.txt in ISO conversion mode.

	      unix2dos a.txt -c iso b.txt

	      unix2dos -c ascii a.txt -c iso b.txt

       Convert and replace a.txt while keeping original date stamp.

	      unix2dos -k a.txt

	      unix2dos -k -o a.txt

       Convert a.txt and write to e.txt.

	      unix2dos -n a.txt e.txt

       Convert a.txt and write to e.txt, keep date stamp of e.txt same as a.txt.

	      unix2dos -k -n a.txt e.txt

       Convert and replace a.txt. Convert b.txt and write to e.txt.

	      unix2dos a.txt -n b.txt e.txt

	      unix2dos -o a.txt -n b.txt e.txt

       Convert c.txt and write to e.txt. Convert and replace a.txt.  Convert and replace b.txt. Convert d.txt and write to f.txt.

	      unix2dos -n c.txt e.txt -o a.txt b.txt -n d.txt f.txt

DIAGNOSTICS

BUGS

       The program does not work properly under MSDOS in stdio processing mode.  If you know why is that so, please tell me.

AUTHOR

       Benjamin Lin - ( blin@socs.uts.edu.au )

MISCELLANY

       Tested environment:

	      Linux 1.2.0 with GNU C 2.5.8

	      SunOS 4.1.3 with GNU C 2.6.3

	      MS-DOS 6.20 with Borland C++ 4.02

       Suggestions and bug reports are welcome.

SEE ALSO

       dos2unix(1)

1995.03.31							   unix2dos v2.2						       unix2dos(1)
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