How to reproduce: `i=0 ; while [ "$i" -lt "60000" ] ; do echo '[20-01-2019 JUST TEXT. JUST TEXT. JUST TEXT. JUST TEXT. JUST TEXT. JUST TEXT. JUST TEXT. JUST TEXT.' >> testfile.txt ; i=$((i+1)) ; done`
Next open testfile.txt CTRL+H and replace [20-01-2019 with [21-01-2019 in whole document. Now replace [21-01-2019 with [22-01-2019 It will freeze for a long time and load one cpu core for 100%. no ram or io load. I set it for a night and it replaced all.