I have a file like thisa   1   5a   1   10a   4   15b   23  29b   23  35b   35  36c   20  50c   20  80I want to get an output in a way like thisa   1   5a   1   10a   4   15b   23  29b   23  35b   35  36c   20  50c   20  80How can I do this? I have a very big file like this and I want to split it when the first column value changes. So like it changes from a to b put a new line and so on.
Manipulating a file to add new lines
shell script;text processing
With awk:awk 'FNR == 1 { old = $1 } $1 != old { old = $1; $0 = \n $0 } 1' file.txt