Using find and sed to rename several subfolders

Question

What I am trying to do is rename folders that are anywhere in the current tree, not neccessarily directly in the working directory. What I need to do is:

• "A 1" becomes "A 01"
• "A 2" becomes "A 02"
• "A 09" is ignored

I ended up with this:

find . -type d -regex '.*A [0-9]$' -execdir mv "{}" "$(echo '{}' | sed 's_[0-9]_0&_')" \;

In order to test this I reduced the complexity a bit:

find . -type d -regex '.*A [0-9]$' -execdir echo "$(echo '{}' | sed 's_[0-9]_0&_')" \;

find lists all folders I want but the pattern in sed does not seem to find a match in the folder names. It works if it is executed on its own, so I guess there is a problem with characters that need to be escaped.

Answer 1

Update: Added a version which can handle any/all valid filename characters, except for \x01, which is used as sed's delimiter.... I have used A.* as the pattern in the updated examples, because I was testing for A"'. Of course, just change to whatever you need.

findx="\(.*/\)\(A.* \)\([0-9]\)$"
replx="&\x00\1\20\3\x00"; I=$'\x01'
find . -depth -type d -regex "$findx" | 
  sed -n "s$I$findx$I$replx$I p" |
    tr -d '\n' | 
      xargs --verbose -0n2 mv 

---

Here is an example, using perl instead of sed.
Note that perl's regualar expressions PCRE are not entirely the same as posix-extended ERE as used by find in this example. They do, however, share enough in common that the same regex pattern can be used in this case.

export findx='(.*/)(A.* )([0-9])$'
find . -depth -type d -regextype posix-extended -regex "$findx" |
  perl -l000pe 's/$ENV{'findx'}/$_\000$1${2}0$3/' |
    xargs --verbose -0n2 mv 

---

These next versions cannot handle single-quotes ' in filenames.

Using standard regex patterns

regex='\(.*/\)\(A \)\([0-9]\)$'
find . -depth -type d -regex "$regex" |
  sed -n "s|$regex|'&' '\1\20\3'|p" |
    xargs --verbose -n2 mv 

To use extended regex paterns

regex='(.*/)(A )([0-9])$'
find . -depth -regextype posix-extended -type d -regex "$regex" |
  sed -nr "s|$regex|'&' '\1\20\3'|p" |
    xargs --verbose -n2 mv 

The -depth option is needed so that more deeply nested directories are renamed before any parent directory is renamed.

Note that the script does not test if a directory already exists with the same name as the new intended name.