I prefer the explicit mangling and unmangling of IFS, though this is also valid for all shells I am aware of.

Background:

VAR1= [VAR2= ...] command

Above line sets and exports the environment variable(s) VAR1, VAR2, … ONLY for the the environment of “command”. It will not change the setting for the current shell.

Example:

#!/bin/sh
while IFS=, read qty product customer
do
# process the information
echo “$customer wants $qty $product(s)”
done < myfile.txt

Using ksh on Solaris, I ran this:

$ set|grep IFS|od -c
0000000 I F S = ‘ \t \n
0000010
$

This shows that IFS consists of a space (” “), a tab (“\t”) and a newline (“\n”).

This is the correct setting for IFS.

“od” stands for “octal dump”, and “od -c” displays each character as a byte. The “0000000″ and “0000010″ are the offsets (in Octal, base 8); the relevant stuff is the “I F S = ‘ \t \n” part.

Hope this helps.

Maybe I should write a post about od some time… it’s a strange and arcane command, but it does sometimes turn out to be very useful.

$ set | grep IFS
HZ=’ ‘
IFS=’
‘

Can someone tell is this IFS environment in KSH set correct by default?

Jonny thanks for your comment regarding line break seperator, it was of great help.

Keep up the good work.

cheers
pai

I think the IFS gets set in your bashrc aka the IFS will get reset when you make a new shell… so if you want sub shells to see your change to IFS remember to use export.

if you want to peek at the value in your IFS, you might try:
printf ‘\n’ “$IFS” | cat -vt
everything between the is the value of your IFS in secret code.

looking at the return of
set | grep IFS
my IFS is set to
IFS=$’ \t\n’
When I open a shell.

Watch out for quotation marks in the CSV… some applications use them, some don’t. Some require them.