Hi folks,

i'm been scratching my head and wondering what's "wrong" (not wrong,
rather not what i expected) with a simple command substitution with
cat command.

for example, i have a tab separated text file:

$ cat foo.txt
a b c
aa bb cc

and i have a shell script:

$ cat foo.sh
#!/bin/sh

for bar in `cat foo.txt`; do
echo "hello world"
done

the execution of this script prints SIX "hello world" rather than TWO
as i expected. it is obvious the variable $bar is assigned the value
of each single word (or one field in the convention of awk) during
each loop and 6 words give 6 loops. while what i need is that a whole
line would be assigned to $bar.

how can i make shell to do what i just described?

thank you very much,
David

David Wang wrote:
>
> for example, i have a tab separated text file:
>
> $ cat foo.txt
> a b c
> aa bb cc
>
> and i have a shell script:
>
> $ cat foo.sh
> #!/bin/sh
>
> for bar in `cat foo.txt`; do
> echo "hello world"
> done
>
> the execution of this script prints SIX "hello world" rather than TWO
> as i expected. it is obvious the variable $bar is assigned the value
> of each single word (or one field in the convention of awk) during
> each loop and 6 words give 6 loops. while what i need is that a whole
> line would be assigned to $bar.
>
> how can i make shell to do what i just described?

while read LINE; do
echo "hello world: $LINE"
done < foo.txt

--
Best regards | "The only way to really learn scripting is to write
Cyrus | scripts." -- Advanced Bash-Scripting Guide

Thanks Cyrus, what you said works for me.

D.

On Aug 30, 4:33 pm, Cyrus Kriticos <cyrus.kriti...@googlemail.com>
wrote:
> David Wang wrote:
>
> > for example, i have a tab separated text file:
>
> > $ cat foo.txt
> > a b c
> > aa bb cc
>
> > and i have a shell script:
>
> > $ cat foo.sh
> > #!/bin/sh
>
> > for bar in `cat foo.txt`; do
> > echo "hello world"
> > done
>
> > the execution of this script prints SIX "hello world" rather than TWO
> > as i expected. it is obvious the variable $bar is assigned the value
> > of each single word (or one field in the convention of awk) during
> > each loop and 6 words give 6 loops. while what i need is that a whole
> > line would be assigned to $bar.
>
> > how can i make shell to do what i just described?
>
> while read LINE; do
> echo "hello world: $LINE"
> done < foo.txt
>
> --
> Best regards | "The only way to really learn scripting is to write
> Cyrus | scripts." -- Advanced Bash-Scripting Guide