Sed empty lines

nc3b · 08-26-2006, 02:51 PM

Hello. First of all, I am not new to Unix but I am quite new to scripting. I am trying to place a word at the beginning of each line using sed. It doesn't work on lines with only one word.

. Both of these commands to the same thing. They put global at the beginning of each line except empty and single-word lines. Please help.

sed '/[^ ] /s/^[^ ]/global &/'g bla2
sed '/[^^$] /s/^[^^$]/global &/'g bla2

randyding · 08-26-2006, 03:14 PM

sed 's/^/global /'
This replaces the beginning of the line with "global " and leaves everything else on the line in tact. The stuff before the first s/ is not necessary in this case, because if you leave it off then sed matches all lines.

nc3b · 08-26-2006, 03:24 PM

Thank you. Actually I needed something that puts global at the beginning of each non-empty line. But I managed to figure that out by myself.

Thank you very much.

/bin/bash · 08-27-2006, 05:17 AM

It's always nice to include the solution to your problem in the thread in case someone else is searching for the same solution in the future.

Put global on empty lines
sed '/^$/s/^/global/g' /path/to/filename

Put global on non-empty lines
sed '/^$/!s/^/global/g' /path/to/filename

sed one-liners

nc3b · 08-27-2006, 06:37 AM

Thank you. Both the examples and the link are great!!!

Edit:
And for those that do not want to match non-empty lines with blank characters:

sed '/[^ ]\{1,\}/ s/^/global /'