[SOLVED] How to replace a string ending with _i with a string starting with i_?

Issue

For example:

input   [TOTAL_CH-1:0]      start_frame_i,  // start of frame

Change to:

input   [TOTAL_CH-1:0]      i_start_frame,  // start of frame

Add on to clarify: There are many different strings are like above.

Solution

GNU sed.

cat file.txt | sed -r 's/(\w+)_i\b/i_\1/g'

(\w+)_i\b

• (\w+)_i matches one or more word character ending with _i and save the string before the _i inside a capturing group(\w+). \b word boundary to ensure it is the end of a word and not to match something like start_frame_iAAA which will result in i_start_frameAAA

i_\1 replace the matched string with, i_ at the beginning and \1 the value which we saved previously inside the capturing group.

Answered By - SaSkY

Answer Checked By - Marilyn (WPSolving Volunteer)