find /root -name ‘*.sql' |xargs -i echo {}   {} |sed ‘s/sql/txt/2′  |xargs mv

find /root/ -name ‘*.sql' |sed -e ‘s/\(.*\).sql$/mv \1.txt/e'     //B哥提供

find /root/ -name ‘*.sql'|awk  ‘{a=$0;sub(/sql$/,”txt”,$0); print “mv”, a,$0}'|bash

find /root/ -maxdepth 1 -name ‘*.sql'|awk  ‘{a=$0;sub(/txt$/,”sql”,$0); system(“mv” ” “a” “$0)}'

for sql in `find /root -name “*.sql”`;do  mv $sql `echo $sql|sed  ‘s/sql/txt/'` ;done

rename  .sql  .txt *.sql  //好像不能遞歸目錄