VIM :-
:set nonu -remove line numbers
:sp file_name ctrl+ww to switch between split sreen
:$ --------------------- go to end of file
:1 ---------------------- go to starting of file 1 number specifies line number
:%s/OLD/NEW/g -- replace OLD string with NEW string globally (g) and in total file %s
:%s/^/NEW/g -- every line at the starting NEW string will be added.
1,30s/rr/aa/gi ----1,30 represent 1 to 30 lines s stands for string rr serch string pattern and aa is replace string g is globally i is case insenditive
ctags * should be enabled at comd prompt
cntl + ] goto function defination
cntl + o come back
cscope -R --- cntl+d exit ,tab to move to bellow cmds