Suppose I have search the string which give like the following result


How I can write generic syntax for grep such it match all 3 string. I have done like this


But I think for indexing eg [1] is not written in good way, how can I achieve so that even i replace [1] with [2342jdsjf], I don't have to change the syntax much.


Using an extended regular expression:

$ grep -E '[[:alnum:]_]+[[:digit:]]+(\[[^]]+\])?\.knownKeyWord' <file

This would extract any line containing a string on the format




where XXX is any non-empty alphanumeric string (that may also include _), NNN is any string of (one or more) digits, and YYY is anything not including a ].

Use grep with -x if matches are to be complete lines. Use -w if matches are supposed to be complete words (i.e. not as a substring of something else).

Just using sed to show what each part of the regular expression is matching:

$ sed -E 's/([[:alnum:]_]+)([[:digit:]]+)(\[[^]]+\])?(\.knownKeyWord)/<\1><\2><\3><\4>/' <file

Try this,

grep -w 'knownKeyWord$' file.txt

From man

-w, --word-regexp

          Select  only  those  lines containing matches that form whole words.  The test is that the matching substring must either be at the beginning of the line, or
          preceded by a non-word constituent character.  Similarly, it must be either at the end of the line or followed by a non-word  constituent  character.   Word-
          constituent characters are letters, digits, and the underscore.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.