How to extract a whole word containing substring

command linetext processing

If I have a file that looks like this:

example.png example.jpg example2.jpg example2.png example.swf
example2.swf example3.jpg example4.jpg example3.png example3.swf

and I want to extract the words containing swf for example, the output would look something like this

example.swf 
example2.swf
example3.swf

I tried grep -o "swf[^[:space:]]*", which just prints a bunch of swf, and then I tried grep -o '[^ ]*a\.swf[^ ]*', which output very few lines containing "swf". Does anyone know what to do?

Best Answer

With GNU grep:

grep -o '\b\w*\.swf\b' file

Output:

example.swf
example2.swf
example3.swf

\b: a zero-width word boundary

\w: word character

\.: match one dot

See: The Stack Overflow Regular Expressions FAQ

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Shell – Grep for string but ignore commented out items with string

With grep:

grep -P '^(?=[\s]*+[^#])[^#]*(gmail|outlook)' file

-P activates Perl compatible regular expressions.
^(?=...) defines a capture group which is not part of the pattern (lookahead; a Perl extenstion). The ^ means the start of the line.
- Inside that group \s matches any whitespace character, *+ matches the whitespace 0 or more times and is greedy (a Perl extension).
- [^#] matches any character which is not a #.
[^#]* outside the capture group we again match any character which is not a # 0 or more times
(gmail|outlook) finally match gmail or outlook

I made a test file with different examples:

$ cat file
# outlook
blah gmail # this should match
# gmail
  # gmail
        # foo
blah outlook # this should match
  outlook blah # gmail - this should match
foobar # gmail
        bar
        another gmail # this should match

The output is:

blah gmail # this should match
blah outlook # this should match
  outlook blah # gmail - this should match
        another gmail # this should match

Of course, you can run this on all your *.ksh files:

grep -P '^(?=[\s]*+[^#])[^#]*(gmail|outlook)' *.ksh  > a.log

Shell – How to print lines containing 3 words

try

 awk 'NF==3' file.txt

this will grep line with 3 field (NF).

Best Answer

Related Solutions

Shell – Grep for string but ignore commented out items with string

Shell – How to print lines containing 3 words

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