extract lines one by one 2

[kasparov]

I have a file with 3 fields separated by spaces & I want to extract each line one by one & then perform some processing on each one. I assumed I could do this:

for line in `cat my_file`
do
do my processing here ...
done

but this extracts each field (so it takes 3 iterations of the for loop to do one line). I'm sure I'm missing something obvious but I just can't think what.

Can anyone help?

 

[DSMARWAY]

hi,

Try this ,

cat my_file | while read A B C
do
process your stuff here using $A $B $C
print $A $B $C
done

HTH

 

[kasparov]

That's it - many thanks!

Chris

 

[jamisar]

please do not reinvent the shell, use its features !!

#!/bin/sh
IFS="\n"
for aaa in `cat filename`
do echo $aaa
done

 

[dickiebird]

Hi DSMARWAY........
Helped me too - but what if the separator isn't a space ?
;-) Dickie Bird
db@dickiebird.freeserve.co.uk

 

[jamisar]

IFS can be set to every chars NOT in the range [A-z0-9_]

 

[kasparov]

Thanks jamisar - I knew there was a way to do it ...!

 

[dchoulette]

I would use DSMARWAY's method.

If you want the whole line in a single variable:

cat ... | while read line; do ...

For a discution about IFS and while read vs for in `cat`, look thread822-302325.

 

[vgersh99]

avoid UUOC [Useless Use of Cat]:

http://groups.google.com/groups?q=U...ell&hl=en&lr=&ie=UTF-8&safe=off&start=30&sa=N

#!/bin/sh
IFS="\n"
for read aaa
do
echo $aaa
done < filename vlad
+---------------------------+
|#include<disclaimer.h> |
+---------------------------+

 

[vgersh99]

ooops - darn copy&paste:

#!/bin/sh
IFS=&quot;\n&quot; while read aaa
do
echo $aaa
done < filename

vlad vlad
+---------------------------+
|#include<disclaimer.h> |
+---------------------------+

 

[vgersh99]

man, am I bad.... sorry

#!/bin/sh
while IFS=&quot;\n&quot; read aaa
do
echo $aaa
done < filename
vlad
+---------------------------+
|#include<disclaimer.h> |
+---------------------------+

 

[olded]

Vlad:

You get a star for pointing out UUOC, and promoting good coding practices.

As a maintenance programmer I won't &quot;fix&quot;a UUOC for fear of breaking something else, but I don't believe in creating new ones.

Thanks!

Ed