topic Re: Easy shell scripting question in Operating System - HP-UX

Easy shell scripting question

Sean OB_1 — Thu, 30 Sep 2004 09:10:11 GMT

I have a file that has 15-20 thousand lines like this:

field1 field11
field222 field22222222

All fields separated by a single space.

I want to run through this script and set a var equal to each of the two fields for a record, then do something else.

EX:

var1=field1
var2=field11

Just looking for the most efficient way to do this.

TIA and points for all responses.

Sean

Re: Easy shell scripting question

Steve Steel — Thu, 30 Sep 2004 09:24:19 GMT

Hi

cat file|while read field1 field2 rest
do
var1=field1
var2=field2
.
.
.
done

See www.shelldorado.com for scripting

Steve Steel

Re: Easy shell scripting question

Rangarajan Radhakrishna — Thu, 30 Sep 2004 09:32:53 GMT

in Korn:
while read var1 var2
do
# something
done < input_file

(If you dont trust input to be nice)
You can also read as:
while THE_LINE=$(line)
do
echo $THE_LINE | read var1 var2
# something
done < input_file

Re: Easy shell scripting question

Dwyane Everts_1 — Thu, 30 Sep 2004 09:35:24 GMT

Sean,

Would something like this work for you?

field1="$(cat | awk '{print $1}') | echo $field2"
field11="$(cat | awk '{print $11}') | echo $field11"

for field1 in `$(cat | awk '{print $1}')`
do
for field11 in `$(cat | awk '{print $11}')`
do
echo $field1 $field11

done
done

Just a couple of ideas. If I had a sample file to test with, I couple probably come up with something a bit more extravagant :)

Dwyane

Re: Easy shell scripting question

Dwyane Everts_1 — Thu, 30 Sep 2004 09:37:16 GMT

Ooooppppssss!!!! A correction

field1="$(cat | awk '{print $1}')"
echo $field1
field11="$(cat | awk '{print $11}')"
echo $field11"

got ahead of myself a little bit :)

Dwyane

Re: Easy shell scripting question

Franky_1 — Thu, 30 Sep 2004 09:41:56 GMT

Hi,

num=1
cat |while read a b
do
echo var$num=$a
let num="num + 1"
echo var$num=$b
done

...assuming that you want the var_num ascending

Regards

Franky

Re: Easy shell scripting question

Geoff Wild — Thu, 30 Sep 2004 09:43:42 GMT

will this work:

cat yourfile | while read line
do
read var1 var2 rest
echo "$var1 $var2"
done

Rgds...Geoff

Re: Easy shell scripting question

Stefan Schulz — Thu, 30 Sep 2004 09:47:41 GMT

Hi,

i think a while read should be the most efficient way to do this.

Something like:

while read var1 var2
do
# do something here
done < yourinputfile

This will run through all lines of yourinputfile and for every line you can do something and use var1 for the first field and var2 for the second field. As in your example in the first loop var1 would be "field1" and var2 would be "field11" (without the " of course). In the second loop var1=field222 and var2=field22222222 and so on.

Hope this helps.

Regards Stefan

Re: Easy shell scripting question

Stefan Schulz — Thu, 30 Sep 2004 09:49:55 GMT

Aahhrg 7 answers bevor mine. The Internet connecto to and from Germany seems to show me the answers of the others only when i post one myselfe.

Never mind.

Stefan

Re: Easy shell scripting question

Muthukumar_5 — Thu, 30 Sep 2004 09:53:28 GMT

We can do as,

while read line; do

var1=$(echo $line | awk '{ print $1 }')
var2=$(echo $line | awk '{ print $2 }')

done <

Re: Easy shell scripting question

Muthukumar_5 — Thu, 30 Sep 2004 10:00:32 GMT

There is a problem that,

if you store first field and second filed on var1 , var2 only last record's information only available there.

So we can avoid this with array simply as,

# Array index
index=0

while read line; do

var1[$index]=$(echo $line | awk '{ print $1 }')
var2[$index]=$(echo $line | awk '{ print $2 }')

let index=index+1

done <

so that

for first record it is saved as,

echo ${var1[1]} ${var2[1]}

and nth record as,

echo ${var1[n]} ${var2[n]}

HTH.

Re: Easy shell scripting question

Franky_1 — Thu, 30 Sep 2004 10:05:11 GMT

Hi Sean,

sorry i've missed one line :-(

num=1
cat |while read a b
do
echo var$num=$a
let num="num + 1"
echo var$num=$b
let num="num + 1"
done

Regards

Franky