meaning of regex

reza_zah1991 · 06-22-2013, 03:04 PM

this command clear space from inputFile & create a new File without space with out.txt Name

sed -e 's/[\t ]//g;/^$/d' $inputFile > $out.txt

's/[\t ]//g;/^$/d'

what is it mean?
how can i expert in this expression?

smallpond · 06-22-2013, 09:46 PM

Code:

s/[\t ]//g;/^$/d
  s    - substitute second for first
  [\t] - first is tab
       - second is nothing
  g    - global, don't stop at first one found
  ;    - there's more
  ^$   - empty line, start is next to end
  d    - delete

So this removes all tabs and blank lines.

theNbomr · 06-22-2013, 11:55 PM

Quote:

Originally Posted by smallpond

Code:

s/[\t ]//g;/^$/d
  s    - substitute second for first
  [\t] - first is tab
       - second is nothing

So this removes all tabs and blank lines.

The second character in the set is a space character. So, the command deletes tabs, spaces, and blank lines.

--- rod.