3

Is there a way to find a specific record among the whole line?

This is my file:

one two three four
two three four five
three four five six
four five six seven
five six seven eight

How do I search for all lines which include two?

5
awk '/(^| )two( |$)/' ...

The (..) groups there are trying to ensure we're only matching "two". At the front it either needs to be the beginning of the line or a space and at the end it needs to be a space or the end of the line. In short, we're making sure the field equals two.

Hmm apparently you can also use word-boundary tags (which looks slightly more elegant but isn't as portable):

awk '/\<two\>' ...

Not sure what your specific use-case is (I assume it's not numbers), you might be just as well off with grep -E '\<two\>' ... but awk will give you a bit more flexibility if you need to do other stuff.

  • thanks, for the second part, ( |$) I understand the usage of space. But for $ part , would you please add why $ stand for in here? {I just know $x refers to column x. – Mohammad Reza Rezwani Jul 9 '14 at 20:05
  • 1
    Simply: the end of the line. ^ means the start. – Oli Jul 9 '14 at 20:12
2

For this simple task you can also use grep:

grep  'two' /path/to/file

output:

one two three four
two three four five

To get the "two" if it is not at the beginning of a line:

grep ' two ' /path/to/file ->one two three four

or with meta-characters to get it only at the beginning of a line:

grep '^two' /path/to/file ->two three four five

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