Shell Programming and Scripting

So I'm on an AIX machine.

And sed is not applying /d "delete line" option when I also include match word options \< and \>

examples...

Code:

echo cat | sed '/\<cat\>/d'

will return cat for some reason

Code:

echo cat | sed "/\<cat\>/d"

will also still return cat.

Of course i can just run

Code:

echo cat | sed '/cat/d'

nothing returned as the /d 'delete line' option is now is applied.
But I need to match the word exactly.... so what am I doing wrong?

Moderator's Comments:

Please use CODE tags as required by forum rules!

As both your examples work on my linux host, but not on FreeBSD, I presume it's your sed version that doesn't like the word delimiters.

Sorry, I was not meaning to double post, I though it would be better to have thread in 'Shell Programming and Scripting ' then here, "programming" So I was going to delete this thread.
Thanks for the reply. still tying to figure out a work around here.

Hi,

This is certainly a messier and less efficient solution, but in the absence of word boundaries in your sed implementation you could maybe do something like this ?

sed -e "/^cat /d" -e "/ cat$/d" -e "/ cat /d"

So specifically checking for lines starting with 'cat' and then a space; lines ending with a space and then 'cat'; and lastly lines containing 'cat' surrounded by a space on either side. And so on in that fashion, if there are any other cases that would occur in your input (you'd have to consider punctuation marks, etc).

As I say, messy, but you could cobble something together in this way maybe.

Moved thread to desired forum.


Adaption of drysdalk's proposal:

Code:

echo "as cat, " | sed -r '/(^|[[:punct:][:space:]])cat([[:punct:][:space:]]|$)/d'

or

Code:

echo "cat, " | sed -r '/(^|[^[:alnum:]])cat([^[:alnum:]]|$)/d'

Thanks for the replies drysdalk and rudic.

drysdalk - I was able to achieve what I wanted from the example of your code!, thanks!

Code:

 sed -e "/^cat /d" -e "/ cat$/d" -e "/ cat /d"

rudic - Sadly the -r option isn't available for sed in AIX, I wasn't able to get your examples to work.

Is the -E option available instead - both have the meaning "use extended regexes"?