perl -pi -e 'if(//){$a=$1};if(//){$_=~s/(/$1$a>/g}' input or perl -pi -e '$a=m/(/;if($a){$2==1?$b=$3:$_=~s/($1)/$1$b/g;}' input or perl -pi -e '$a=m/(/;$a?$2==1?$b=$3:$_=~s/($1)/$1$b/g:next;' input or perl -pi -e '$a=m;(;;$a?$2==1?$b=$3:$_=~s;($1);$1$b;g:1;' input #### perl -pi -e 'm;(;;$&?$2==1?$b=$3:$_=~s;($1);$1$b;g:1;' input #### perl -pi -e 'm;(;;$&?$2==1?$b=$3:$_=~s;($1);$1$b;g:1' input #### perl -pi -e '/l1(\sid=.*)>/?$a=$1:s;l2>;l2$a>;' input