Shell Programming and Scripting

ok, apparently this is a very difficult question to answer based on my searches on google that came up fruitless.

what i want to do is grep through a file for words that match a specified string.

but the thing is, i keep getting all words in the file that have the string in them.

say for instance all I want from a file is the word "airplane". I want to replace this word "airplane" with "helicopter".

the problem is, in the file i'm using, there are several occurrences of the word "airplane". example: "airplanewomen, airplaneman, sweetairplane, sourairplane".

When i go to look for the word airplane, all these other strings come up, and I dont want them.

does anyone know of a way to grep out just the occurences of only the word "airplane" from a file?

by the way, grep -w doesn't work, neither does grep -x. neither those grep "^string".

i'm using ubuntu 8.

try grep " airplane " or grep " airplane." for end of line

grep "^airplane$"

i've actually tried this but nothing shows up.

do you know how sed can be used for this?

this seems to work. but how do i incorporate it into sed to replace just the occurences of airplane?

try this ...

Code:

sed 's:\<airplane\>:helicopter:g'  filename

your code seems like it might do the trick. but let me give a bit more explanation of the problem im having.


sometimes in the file i'm using, there are words like this: db-airplane, db-12.airplane.

in cases like that, your code turns the words into db-helicopter, db-12.helicopter.

you see what i'm saying? I dont want the code to touch anything in the file that isn't "airplane", alone. all i want is to replace places were the airplane stands alone.

thanks you so much for your suggestions