Shell Programming and Scripting

#!/bin/bash

for file in *.txt
do
        num="${file%%-*}"
        nam="${file##*-}"
        printf "%02d-%s\n" $num $nam
done

for file in *.txt
do
  [[ ${file%%-*} -ge 10 ]] && continue
   echo "mv $file 0$file"
done

for i in [0-9]\ *
do      mv "$i" "0$i"
done

mv: cannot stat `[0-9] *': No such file or directory

01-abcd1.txt
02-abcd2.txt
...
...
09-abcd9.txt

If i will move them back to 

1-abcd1.txt
2-abcd2.txt
...
...
9-abcd9.txt

I have tried below code but not working. Please advice.

for file in *.txt
do
  [[ ${file%%-*} -ge 10 ]] && continue
   echo "mv 0$file $file"
done