topic Re: Script help - reading mulple lines into variables from command execution in Operating System - HP-UX

Script help - reading mulple lines into variables from command execution

Jack C. Mahaffey — Tue, 01 Jun 2004 07:50:45 GMT

I want to be able to execute a command, do some greps on the output and then assign the output columns to variables within a loop. There's got to be a way to do this without saving the ouput to a file and then reading the file.

Any examples to share?

Thanks...
Jack

----------------------------------

Example:
while read -r field1 field2 field3 field4 field5 field6 field7 field8 field9 field10
do
echo $field1
done < lanscan | grep -v "^Path" | grep -v "^Hardware" | awk ' { print $1 " " $2 " " $3 " " $4 \ " " $5 " " $6 " "
$7 " " $8 " " $9 " " $10 } '
---------------------------------

Re: Script help - reading mulple lines into variables from command execution

harry d brown jr — Tue, 01 Jun 2004 08:33:23 GMT

How about a little perl?

#!/usr/bin/perl
open(INFILEPTR,"lanscan |") || die "unable to find lanscan";
while () {
next if (grep(/^Path/,$_));
next if (grep(/^Hardware/,$_));
tr/ / /s;
($field1, $field2, $field3, $field4, $field5, $field6, $field7, $field8, $fie
ld9, $field10) = split(/ /);
print $field1,"_" ,$field2,"_", $field3,"_", $field4,"_", $field5,"_", $field6,"_", $field7,"_", $field8,"_", $field9,"_", $field10;
}

live free or die
harry

Re: Script help - reading mulple lines into variables from command execution

Jack C. Mahaffey — Tue, 01 Jun 2004 08:38:32 GMT

Thanks Harry.. Love the script. I'd also like to get the shell version also. I'll be using the perl version.

Jack...

Re: Script help - reading mulple lines into variables from command execution

curt larson_1 — Tue, 01 Jun 2004 09:29:35 GMT

how about trying it this way

lanscan |
grep -v "^Path" |
grep -v "^Hardware" |
awk ' { print $1 " " $2 " " $3 " " $4 \ " " $5 " " $6 " "$7 " " $8 " " $9 " " $10 } ' |
while read -r field1 field2 field3 field4 field5 field6 field7 field8 field9 field10
do
echo $field1
done

instead of all the greps and awk you could just do
awk '
/^Path/ {next;}
/^Hardware/ {next;}
{ print $1 " " $2 " " $3 " " $4 \ " " $5 " " $6 " "$7 " " $8 " " $9 " " $10 } '

or

while read -r field1 field2 field3 field4 field5 field6 field7 field8 field9 field10
do
echo $field1
done < $(lanscan | grep -v "^Path" | grep -v "^Hardware" | awk ' { print $1 " " $2 " " $3 " " $4 \ " " $5 " " $6 " "
$7 " " $8 " " $9 " " $10 } ')

Re: Script help - reading mulple lines into variables from command execution

Jack C. Mahaffey — Tue, 01 Jun 2004 09:54:42 GMT

Curt, your first example worked. The second did not. I might have a typo somewhere.

Jack

Re: Script help - reading mulple lines into variables from command execution

Geoff Wild — Tue, 01 Jun 2004 10:46:42 GMT

second way works if you remove the
\
before the $5

Rgds...Geoff

lanscan | awk ' ^J/^Path/ {next;}^J/^Hardware/ {next;}^J{ print $1 " " $2 " " $3 " " $4 " " $5 " " $6 " "$7 " " $8 " " $9 " " $10 } '

Re: Script help - reading mulple lines into variables from command execution

Jack C. Mahaffey — Tue, 01 Jun 2004 10:50:33 GMT

I caught the backslash... Still didn't work. I'll check it again.

Re: Script help - reading mulple lines into variables from command execution

curt larson_1 — Tue, 01 Jun 2004 12:53:31 GMT

no i couldn't get the second example to work either, but here is another way

lanscan | grep -v "^Path" | grep -v "^Hardware" | awk ' { print $1 " " $2 " " $3 " " $4 " " $5 " " $6 " "
$7 " " $8 " " $9 " " $10 } ' |&

while read -rp field1 field2 field3 field4 field5 field6 field7 field8 field9 field10
do
echo $field1
done

hey 2 out of 3 ain't bad

Re: Script help - reading mulple lines into variables from command execution

Jack C. Mahaffey — Tue, 01 Jun 2004 13:17:26 GMT

I like the last example also. What specifically does the "&" and -p do? Is & a reserved variable?

Re: Script help - reading mulple lines into variables from command execution

Jack C. Mahaffey — Tue, 01 Jun 2004 13:22:03 GMT

I noticed that both |& need concatenated with no space in order for it to work.

Re: Script help - reading mulple lines into variables from command execution

Rodney Hills — Tue, 01 Jun 2004 13:26:52 GMT

& on the end of line means run as a detached process. |& means to run detached, but as a co-process. This allows read -p to get its input from the co-process. Some documentation under "man ksh"

-- Rod Hills