[nylug-talk] noob bash sed confusion

[Yusuke Shinyama]

On Thu, 02 Nov 2006 18:33:42 -0500, jh <jhlists at hirschman.net> wrote:
> I'm trying to use sed in bash, and i'm getting rather confused with 
> quotes and escapes. I'm hoping that someone can help...
> 
> OK, this works fine from the bash prompt:
> 
> sed -e 's/source\ src\ {/source\ src\ 
> {unix-stream("\/home\/foo2\/dev\/log");/g' file.txt
> 
> I'd like to do the same thing, but use a variable for the replace 
> argument instead of foo2. How can I do this within a bash script?

You can mix single and double-quoted strings within one argument:

$ i=2
$ echo '1'"$i"'3'
123

Also, you don't have to use always a / for the pattern delimiter.
So...

$ for i in a b c; do echo sed -e 's.source src {.source src {unix-stream("/home/'"$i"'/dev/log");.g' file.txt; done
sed -e s.source src {.source src {unix-stream("/home/a/dev/log");.g file.txt
sed -e s.source src {.source src {unix-stream("/home/b/dev/log");.g file.txt
sed -e s.source src {.source src {unix-stream("/home/c/dev/log");.g file.txt

Yusuke