strange behaviour from sed???


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# 1  
strange behaviour from sed???

Hi all,

I want to do a very simple thing with sed. I want to print out the line number of a disk I have defined in /etc/exports, so I do:

Quote:
# sed -n '/md0/=' /etc/exports
3
It's all good, but here's the problem. When I define md0 in a variable, I get nothing from sed:

Quote:
# dev="md0"
# echo $dev
md0
# sed -n '/$dev/=' /etc/exports
#

Why is that? can anybody please help?

Thanks
# 2  
Hammer & Screwdriver Try adjusting your syntax

Code:
> cat file9
/usr/bin/bash
/usr/bin/ksh
/usr/bin/me
/mdo/here/there
/jkl/lost/not
> dev=mdo
> echo $dev
mdo
> sed -n '/mdo/=' file9
4
> sed -n "/mdo/=" file9
4
> sed -n "/"$dev"/=" file9
4

# 3  
Quote:
Originally Posted by alirezan
Hi all,
Hi all,

I want to do a very simple thing with sed. I want to print out the line number of a disk I have defined in /etc/exports, so I do:

Code:
# sed -n '/md0/=' /etc/exports
3

It's all good, but here's the problem. When I define md0 in a variable, I get nothing from sed:

Code:
# dev="md0"
# echo $dev
md0
# sed -n '/$dev/=' /etc/exports
#

Why is that? can anybody please help?

Variables are not expanded inside single quotes; use double quotes:

Code:
sed -n "/$dev/=" /etc/exports

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