How to rename a file into a random GUID?

Question

The task is to replace a file's (actually of all the files in a directory) name (but leave extension intact) with a random UUID/GUID. Any ideas on how to do this?

Answer 1

Similar to bahamat answer, but generates actual UUIDs. UUIDs have some reserved bits that are used to determine the version and variant used. There are currently 5 types of UUIDs defined, random UUIDs, as you asked, are version 4. You will note that version 4 UUIDs have this format:

442b7f35-f33f-4b8d-9a07-db8ec207129e
              |    '-- variant (bits 10__ -> [89AB])
              '------- version (bits 0100 -> 4)

Also, this version doesn't cause damage in case the UUID generation fails.

for i in *; do uuid=$(uuidgen -r) && mv -- "$i" "$uuid.${i##*.}" done

Using /proc/sys/kernel/random/uuid:

for i in *; do uuid=$(cat /proc/sys/kernel/random/uuid) && mv -- "$i" "$uuid.${i##*.}" done

Answer 2

Something like this:

for i in *; do mv -- "$i" "$(openssl rand -hex 16).${i##*.}"; done

Using openssl rand 16 gives you 128 bit GUIDs. Use 32 if you want 256 bit GUIDs.

Answer 3

Short Perl script below - the use of cat to get the uuid isn't the cleanest/fastest way to code it, but it keeps the command short:

perl -e '
  foreach (@ARGV) {
    my $uid=qx|cat /proc/sys/kernel/random/uuid|;
    chomp $uid;
    (my $new=$_)=~s#(.*)\.#$uid.#;
    rename($_, $new)
  }
' *.file_ext

The above uses a file in /proc on linux as a source of uuids:

[bash#] cat /proc/sys/kernel/random/uuid
d474706f-b18c-4e4b-8762-5ed577c74ac3