For loop -> reading variables from a text file.

[Jeff Martin_3]

I want to create a script that will run the opcnode command (OV) and feed it multiple entries from a text file with multiple columns. Each column will contain a certian variable.

>opcnode -add_node node_name=VARIABLE1 net_type=NETWORK_IP mach_type=MACH_OTHER group _name=VARIABLE2 node_label=VARIABLE3

In other words I want to feed the above command from a text file file which will contain VARIABLE1 VARIABLE2 VARIABLE3

I know how to do this in NT but not in UNIX.

[curt larson_1]

#!/usr/bin/sh

cat yourFile |
while read v1 v2 v3
do
opcnode -add_node node_name=v1 net_type=NETWORK_IP mach_type=MACH_OTHER group _name=v2 node_label=v3

if [[ "$?" != "0" ]] ;then
your message
fi
done

[curt larson_1]

oops forgot the '$' in front of the v's

opcnode -add_node node_name=v1 net_type=NETWORK_IP mach_type=MACH_OTHER group _name=v2 node_label=v3

should be

opcnode -add_node node_name=$v1 net_type=NETWORK_IP mach_type=MACH_OTHER group _name=$v2 node_label=$v3

[Sridhar Bhaskarla]

Hi,

while read VARIABLE1 VARIABLE2 VARIABLE3
do
opcnode -add_node node_name=$VARIABLE1 net_type=NETWORK_IP mach_type=MACH_OTHER group _name=$VARIABLE2 node_label=$VARIABLE3
done < file

Where file is your text file.

-Sri

[S.K. Chan]

Another way of doing this ..(say your file is /tmp/data)..
#!/usr/bin/sh

exec 0while read -r VAR1 VAR2 VAR3
do
opcnode -add_node node_name=$VAR1 net_type=NETWORK_IP mach_type=MACH_OTHER group _name=$VAR2 node_label=$VAR3
done

[Jeff Martin_3]

What does this do?

if [[ "$?" != "0" ]] ;then
your message
fi
done

[S.K. Chan]

The $? is a special var that store the status (if you will) of the previously executed command. If $? is 0 (zero) it means a success, if non-zero it means failed return status. For example ..
$ date
$ echo $?
0
$ ls myfile
myfile not found
$ echo $?
2
So the body of the if statement will be executed if the previous executed command fails.

[Renda Skandier]

If the text file is one line & you want to break it into columns try:
var1=`cat txtfiles | cut -c1-5`
var2=`cat txtfiles | cut -c6-10`

where c1 is the 1st char of line thru last char
& c6 is the the 1st char of 2nd field

[Donny Jekels · Accepted solution]

This is easier accomplished on unix than on nt!

start with a while loop that reads the contents of a flat file into variables.

while read var1 var2 var3
do
opcnode -add_node node_name=${var1}net_type= mach_type= group _name=${var2} node_label=${var3}
if [[ $? -eq 0 ]]
then
# your job passed ok without any errors
echo "passed ${var1}"
else
echo "failed ${var1}"
fi
done < file


the $?

contain the exit code for the last command.
in unix, 0 (zero) always indicate a success, unless otherwise noted.

see the man page for the command, it always has the exit code towards the bottom.


live free or die
donny