The first thing you want to check is the grep documentation. This together with a few practice with hashes will easily solve your problem.

Many people here get upset with these questions that read like "Hey, I have a problem. Gimme a solution for free. Oh, I don't mind if you improve on what I didn't tell you." Take a look at how Problem in date checking script was received by comments Re: Problem in date checking script and Re: Problem in date checking script. The reference How (Not) To Ask A Question will be a good reading for you as well. It will bring you more sympathetic and useful answers, while helping you to revert your negative XP score.

A one-liner such as this may count the number of lines the word "hello" was found, just like $ grep hello text.out | wc -l (mentioned by derby at Re: grep command).

$ perl -n -e '$count++ if /\bhello\b/; END { print $count }' text.out
[download]

A very simple modification will give you what you want. It has to do with the global modifier in regexes (see perlretut).

Note: I've changed the simple /hello/ to /\bhello\b/ because sanku said he was looking for words.

To get the lines and the count (which is what I think the OP wants):

perl -ne 'if (/\bhello\b/) { print; $count++ } END { print "count: $count\n" }' text.out

And if you want to find "hello" regardless of capitalization:

perl -ne 'if (/\bhello\b/i) { print; $count++ } END { print "count: $count\n" }' text.out

Also, grep from the command line doesn't need wc's help:

grep -c hello text.out

It can match regardless of case too:

grep -ic hello text.out

Well, I was going to give a snarky answer ($ grep hello text.out | wc -l) but then I realized that would only give the number of lines hello appears on. Soooo ... why don't you show us what code you have so far.

just cheat and make sure the input doesn't have more than one per line :)

tr ' ' '\n' < /tmp/hh | grep -c hello
[download]

alternatives:

plain, explicit count (leverage s/// to provide # per line):

perl -lne '$ct += s/hello//g; END {print $ct}' /tmp/hh
[download]

Same technique as the tr/grep above, just in perl flavor:

perl -0040 -ne 'END {print "$x\n"} $x++ if /hello/' /tmp/hh
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Fun w/perlrun:

perl -Fhello -0777 -lane 'print $#F' /tmp/hh

# shorter:
perl -apFhello -0777e '$_=$#F'  < /tmp/hh

# with check for word boundry (e.g. to exclude "Othello" or mispelled 
+"cello")
perl -apF'\bhello\b' -0777e '$_=$#F'  < /tmp/hh
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perl -lne '$ct += s/hello//g; }{print $ct' /tmp/hh
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;-)
--shmem

snarky useless use of wc -l. Use grep -c hello text.out ;-)

scnr,
--shmem

snark the snarkiness. I like it - ++. I hereby ask for forgiveness for all the extra processes I have abused over the years.

-derby

# perl -le'$cnt+=@{[m/\bhello\b/g]}for"aahello hello hello","bb heelo 
+hello phello";print$cnt'
3
[download]

That's the simple modification I told about:

<Reveal this spoiler or all spoilers in this node or all in this thread>

And to answer kyle at Re^2: grep command, my interpretation was that he was concerned about how many times the word happened with no concern for which particular lines. But then he tells about grepping — so if the issue is finding the lines and then telling how many times it appeared in total, this one may work:

<Reveal this spoiler>

Almost!

However, the last line in which "hello" is found is printed twice.

CLI: perl -n -e "print, $count++ while /\bhello\b/g; END { print $count }" hello.out
        (quotes revised for windows)

file hello.txt:
hello. hellow, world. bye
world says hello.
bye
hello, hellow, hello
not now.
done.


output
hello. hellow, world. bye
world says hello.
hello, hellow, hello
hello, hellow, hello
4

I don't see it as a *simple* spoiler, as people quite often try it in scalar context like

$cnt += m{pattern}g;

which doesn't work as they expect.


Enjoy, Have FUN! H.Merijn