Automate renaming of video files

Question

I have a lot of files I want to rename and it would take me a long time to do them manually. They are video files and are usually in this format - \"NAME OF SHOW - EPISODE N

Answer 1

The following solution:

• works with both 3-digit and 4-digit season+episode specifiers (e.g. 107 for season 1, episode 7, or 1002 for season 10, episode 2)
• demonstrates advanced find and bash techniques, such as:
  • the -regex primary to match filenames by regular expression (rather than wildcard pattern, as with -name)
  • execdir to execute a command in the same directory as each matching file (where {} contains the matching file name only)
  • invoking an ad-hoc bash script that demonstrates regular-expression matching with =~ and capture groups reported via the built-in ${BASH_REMATCH[@]} variable; command substitution ($(...)) to left-pad a value with zeros; variable expansion to extract substrings (${var:n[:m]}).

# The regular expression for matching filenames (without paths) of interest:
# Note that the regex is partitioned into 3 capture groups 
# (parenthesized subexpressions) that span the entire filename: 
#  - everything BEFORE the season+episode specifier
#  - the season+episode specifier,
#  - everything AFTER.
# The ^ and $ anchors are NOT included, because they're supplied below.
fnameRegex='(.+ - )([0-9]{3,4})( - .+)'

# Find all files of interest in the current directory's subtree (`.`)
# and rename them. Replace `.` with the directory of interest.
# As is, the command will simply ECHO the `mv` (rename) commands.
# To perform the actual renaming, remove the `echo`.
find -E . \
 -type f -regex ".+/${fnameRegex}\$" \
 -execdir bash -c \
   '[[ "{}" =~ ^'"$fnameRegex"'$ ]]; se=$(printf "%04s" "${BASH_REMATCH[2]}");
   echo mv -v "{}" "${BASH_REMATCH[1]}S${se:0:2}E${se:2}${BASH_REMATCH[3]}"' \;