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sed not applying /d "delete line" option


 
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# 1  
sed not applying /d "delete line" option

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:
Mod Comment Please use CODE tags as required by forum rules!

Last edited by RudiC; 03-10-2017 at 10:55 AM.. Reason: Added CODE tags.
# 2  
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.
# 3  
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.
# 4  
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.
# 5  
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'


Last edited by RudiC; 03-10-2017 at 01:10 PM..
# 6  
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.
# 7  
Is the -E option available instead - both have the meaning "use extended regexes"?

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