Shell Programming and Scripting

Hi

I tried to put underscore in place of column in a big file with lots of oclumns using the programm

Code:

  sed 's/[\t]/_/g'

Its showing error

if input is like these so many columns

Code:

AST3  GUD  GDY

JHF    HGA   HAY

I want output shuld be

Code:

AST3_GUD_GDY

JHF_HGA_HAY

Kindly guide

Try (GNU sed):

Code:

$ sed 's/[ \t]\+/_/g' infile
AST3_GUD_GDY

JHF_HGA_HAY

I think you're just missing the space before the filename...

its placing underscore even if there is some space within a columns which I dont want

for eg

if there are 3 columns

Code:

AST not available  sht

its shows

Code:

AST_not_available_sht

but I want it shuld show

Code:

AST_not available_sht

so there is an error.

That's a new aspect. Please show a representative input example and a related output example. Also describe the rules when and where something should be substituted to avoid that people keep guessing or requirements are different inbetween posts, thanks.

Hi

As I mentioned above only column has to be replce with underscore no change within the column has to be made and I made it clear by citing above sample example no other chsnge has to be made. Kindly guide if possible.

manigrover, in your 1st example you want all spaces replaced by an underscore. In the second example it seems you have this:

Code:

AST not available  sht

This is a very limited excerpt. From a look of awk this has 4 columns, not 3, since a blank, space and tabs form a field separator and in your input there is nothing but blanks as separator.
One could parse that if the line contains "not available", that this is protected from substitution, but I bet you have more than this line - else you would not need a script.

So to help you describing your input, is there just 3 columns usually and when it is 4, then there is the string "not available" in there or is there even more kinds of different lines.