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up vote 4 down vote favorite
1

I want to run a command that gives the following output and parse it:

[VDB VIEW]
[VDB] vhctest
        [BACKEND] domain.computername: ENABLED:RW:CONSISTENT
        [BACKEND] domain.computername: ENABLED:RW:CONSISTENT
        ...

I'm only interested in some key works, such as 'ENABLED' etc. I can't search just for ENABLED as I need to parse each line at a time.

This is my first script, and I want to know if anyone can help me?

EDIT: I now have:

cmdout=`mycommand`

while read -r line
do
   #check for key words in $line
done < $cmdout

I thought this did what I wanted but it always seems to output the following right before the command output.

./myscript.sh: 29: cannot open ... : No such file

I don't want to write to a file to have to achieve this.

Here is the psudo code:

cmdout=`mycommand`

loop each line in $cmdout
   if line contains $1
       if line contains $2
            output 1
       else
            output 0
share|improve this question
    
@Mr Shoubs - hmmm ... try YOUR_COMMANDS | grep -e "YOUR_KEYWORD1\|YOUR_KEYWORD2\|..." Or pipe the output into a file –  ajreal Nov 25 '10 at 12:19
    
Each keyword I am searching for is mutually exclusive - for example, I want to know what keyword each line contains. this will eventually be used with Nagios. –  Mr Shoubs Nov 25 '10 at 12:25

3 Answers 3

up vote 4 down vote accepted

The reason for the error is that

done < $cmdout

thinks that the contents of $cmdout is a filename.

You can either do:

done <<< $cmdout

or

done <<EOF
$cmdout
EOF

or

done < <(mycommand)    # without using the variable at all

or

done <<< $(mycommand)

or

done <<EOF
$(mycommand)
EOF

or

mycommand | while
...
done

However, the last one creates a subshell and any variables set in the loop will be lost when the loop exits.

share|improve this answer
up vote 2 down vote

"How can I read a file (data stream, variable) line-by-line (and/or field-by-field)?"

"I set variables in a loop. Why do they suddenly disappear after the loop terminates? Or, why can't I pipe data to read?"

share|improve this answer
    
I'll have a look, but I'm not reading from a file. –  Mr Shoubs Nov 25 '10 at 12:20
    
You can be, with piping or process substitution. –  Ignacio Vazquez-Abrams Nov 25 '10 at 12:21
up vote 0 down vote 
$ cat test.sh
#!/bin/bash
while read line ; do
if [ `echo $line|grep "$1" | wc -l` != 0 ]; then
    if [ `echo $line|grep "$2" | wc -l` != 0 ]; then
        echo "output 1"
    else
        echo "output 0"
    fi
fi

done

USAGE

$ cat in.txt | ./test.sh ENABLED  RW
output 1
output 1

This isn't the best solution, but its a word by word translation of what you want and should give you something to start with and add your own logic

share|improve this answer
    
if echo "$line" | grep -q "$1"; then - no need for backticks, brackets, wc or != 0 –  Dennis Williamson Nov 25 '10 at 15:12

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