A quick one… pretty simple but I wanted to make note of it.
I unwisely numbered the files in a folder like so:
1.txt
2.txt
...
9.txt
10.txt
11.txt
12.txt
So their alphanumeric order is not the same as the numeric order. Is there a quick way in the shell to renumber these with leading zeros? Of course.
for a in [0-9]*.txt; do # match numbered files
mv $a `printf %02d.%s ${a%.*} ${a##*.}` # replace number with 2-digit ver.
done