How to recursively rename files and folder with iconv from Bash - linux

I have been trying to recursively rename files AND folders with iconv without success, the files are correctly renamed but folders dont.
What I use for files is (works perfect):
find . -name * -depth \ -exec bash -c 'mv "$1" "${1%/*}/$(iconv -f UTF8 -t ASCII//TRANSLIT <<< ${1##*/})"' -- {} \;
What I tried for files AND folders (fail: Only rename folders):
find . -exec bash -c 'mv "$1" "$(iconv -f UTF8 -t ASCII//TRANSLIT <<< $1)"' -- {} \;
ORIGINAL problem:
I just want to bulk rename lots of files to make them "web friendly", thinks like removing spaces, weird characters and so on, currently I have
find . -name '*' -depth \
| while read f ;
do
mv -i "$f" "$(dirname "$f")/$(basename "$f"|tr -s ' ' _|tr -d "'"|tr -d ","|tr - _|tr "&" "y"|tr "#" "a")" ;
done
Is there any way to do the tr stuff above and the iconv at a single run? because I am talking around 300,000 files to rename, I would like to avoid a second search if possible.
If needed, I am working with Bash 4.2.24
Thanks in advance.

I think the following does everything you want in one pass.
# Update: if this doesn't work, use read -d '' instead
find . -print0 | while IFS= read -d '$\000' f ;
do
orig_f="$f"
# Below is pure bash. You can replace with tr if you like
# f="$( echo $f | tr -d ,\' | tr "$'&'#- " "ya__" )"
f="${f// /_}" # Replace spaces with _
f="${f//\'}" # Remove single quote
f="${f//-/_}" # Replace - with _
f="${f//,}" # Remove commas
f="${f//&/y}" # Replace ampersand with y
f="${f//#/a}" # Replace at sign with a
f=$( iconv -f UTF8 -t ASCII//TRANSLIT <<< "$f" )
new_dir="$(dirname $f)"
new_f="$(basename $f)"
mkdir -p "$new_dir"
mv -i "$orig_f" "$new_dir/$new_f"
done
The find command (no real options needed, other than -print0 to handle filenames with spaces) will send null-separated file names to the while loop (and someone will correct my errors there, no doubt). A long list of assignments utilizing parameter expansion removes/replaces various characters; I include what I think is the equivalent pipeline using tr as a comment. Then we run the filename through iconv to deal with character set issues. Finally, we split the name into its path and filename components, since we may have to make a new directory before executing the mv.

Here is an update I offer after chepner's answer to avoid nesting bugs. Reverse the output of find with tac to act on folders content before the folders themselves. This way, there is no need to mkdir anymore:
echo "renaming:"
find . -print0 | tac -s '' | while IFS= read -d '' f ;
do
Odir=$(dirname "$f") # original location
Ofile=$(basename "$f") # original filename
newFile=$Ofile
# remove unwanted characters
newFile=$(echo $newFile | tr -d ",'\"?()[]{}\\!")
newFile="${newFile// /_}" # Replace spaces with _
newFile="${newFile//&/n}" # Replace ampersand with n
newFile="${newFile//#/a}" # Replace at sign with a
newFile=$( iconv -f UTF8 -t ASCII//TRANSLIT <<< "$newFile" )
if [[ "$Ofile" != "$newFile" ]]; then # act if something has changed
echo "$Odir/$Ofile to"
echo "$Odir/$newFile"
mv -i "$Odir/$Ofile" "$Odir/$newFile"
echo ""
fi
done
echo "done."
Enjoy ;)

Related

Recursively get all the files and dirs they are located in

Trying to run a script that will fetch all directories, and files containing these directories, and logs data onto a .CSV file.
So, if I were to have structure like:
mainDir.dir -> [sub1.dir -> file01.png, sub2.dir -> file02.png]
, I would get a CSV of
dir; file
sub1; file01.png
sub2; file02.png
This is the script I currently have
for dir in */ .*/ ;
do
for entry in $dir
do
path="$entry"
empty=""
file="${$dir/$empty}"
echo -e "$dir;$file;" >> file.csv
done
done
find is useful for processing many files recursively.
Command
find . -type f -execdir sh -c "pwd | tr -d '\n' >> ~/my_file.csv; echo -n ';' >> ~/my_file.csv; echo {} | sed -e 's/^\.\///' >> ~/my_file.csv" \;
Note: make sure you do not give a relative path to the output CSV file. execdir changes the working directory (and that is what makes pwd work).
Breakdown
find . -type f find all files recursively starting here
-execdir sh -c "pwd | tr -d '\n' >> ~/my_file.csv; echo -n ';' >> ~/my_file.csv; For each file, execute in its directory pwd. Strip the newline and add directory name to output. Also add a semicolon, again with no newline.
echo {} | sed -e 's/^\.\///' >> ~/my_file.csv" \; Append filename to output. This time, leave newline, but by default find will place the ./ in front of the filename. The sed here removes it.
If you don't need more than one level deep, this seems to work
for i in **/*; do echo $i | tr / \; ; done >> file.csv

How to use sed to change file extensions?

I have to do a sed line (also using pipes in Linux) to change a file extension, so I can do some kind of mv *.1stextension *.2ndextension like mv *.txt *.c. The thing is that I can't use batch or a for loop, so I have to do it all with pipes and sed command.
you can use string manipulation
filename="file.ext1"
mv "${filename}" "${filename/%ext1/ext2}"
Or if your system support, you can use rename.
Update
you can also do something like this
mv ${filename}{ext1,ext2}
which is called brace expansion
sed is for manipulating the contents of files, not the filename itself. My suggestion:
rename 's/\.ext/\.newext/' ./*.ext
Or, there's this existing question which should help.
This may work:
find . -name "*.txt" |
sed -e 's|./||g' |
awk '{print "mv",$1, $1"c"}' |
sed -e "s|\.txtc|\.c|g" > table;
chmod u+x table;
./table
I don't know why you can't use a loop. It makes life much easier :
newex="c"; # Give your new extension
for file in *.*; # You can replace with *.txt instead of *.*
do
ex="${file##*.}"; # This retrieves the file extension
ne=$(echo "$file" | sed -e "s|$ex|$newex|g"); # Replaces current with the new one
echo "$ex";echo "$ne";
mv "$file" "$ne";
done
You can use find to find all of the files and then pipe that into a while read loop:
$ find . -name "*.ext1" -print0 | while read -d $'\0' file
do
mv $file "${file%.*}.ext2"
done
The ${file%.*} is the small right pattern filter. The % marks the pattern to remove from the right side (matching the smallest glob pattern possible), The .* is the pattern (the last . followed by the characters after the .).
The -print0 will separate file names with the NUL character instead of \n. The -d $'\0' will read in file names separated by the NUL character. This way, file names with spaces, tabs, \n, or other wacky characters will be processed correctly.
You may try following options
Option 1 find along with rename
find . -type f -name "*.ext1" -exec rename -f 's/\.ext1$/ext2/' {} \;
Option 2 find along with mv
find . -type f -name "*.ext1" -exec sh -c 'mv -f $0 ${0%.ext1}.ext2' {} \;
Note: It is observed that rename doesn't work for many terminals
Another solution only with sed and sh
printf "%s\n" *.ext1 |
sed "s/'/'\\\\''/g"';s/\(.*\)'ext1'/mv '\''\1'ext1\'' '\''\1'ext2\''/g' |
sh
for better performance: only one process created
perl -le '($e,$f)=#ARGV;map{$o=$_;s/$e$/$f/;rename$o,$_}<*.$e>' ext2 ext3
well this should work
mv $file $(echo $file | sed -E -e 's/.xml.bak.*/.xml/g' | sed -E -e 's/.\///g')
output
abc.xml.bak.foobar -> abc.xml

Using bash, how do I find all files containing a specific string and replace them with an existing file?

I am using Linux and would like to replace all files containing the string 000000 with an existing file /home/user/offblack.png but keep the existing filename. I've been working at this for a while with various combinations of -exec and xargs but no luck. So far I have:
find | grep 000000
Which does list all the files I want to change fine. How do I copy and replace these files with my existing offblack.png file?
Here's what I would use:
find (your find args here) \
| xargs fgrep '000000' /dev/null \
| awk -F: '{print $1}' \
| xargs -n 1 -I ORIGINAL_FILENAME /bin/echo /bin/cp /path/to/offblack.png ORIGINAL_FILENAME
Expanding, find all the files you're interested in, grep inside of them for the string '000000' (adding /dev/null to the list of files in case one of the generated fgreps ended up with only one filename - it ensures the output is always formatted as "filename: <line containing '000000'>"), strip out only the filenames, then one-by-one, copy in offblack.png over those files. Note that I inserted a /bin/echo in there. That's your dry-run. Remove the echo to get it to run for real.
If what you mean is that the filenames contain "000000":
find . -type f -a -name '*000000*' -exec /bin/echo /bin/cp /path/to/offblack.png {} \;
Much simpler. :-) Find every file under the current directory with a name containing your string and exec the copy of offblack.png over it. Again, what I've given you there is a dry-run. Remove the echo for your live fire drill. :-)
find . -type f | grep 000000 | tr \\n \\0 | xargs -0i+ cp ~/offblack.png "+"
Let's try and use Bash a bit more:
for read -r filename
do
hit=""
for read -r
do
if [[ $REPLY == *000000* ]]
then
hit=$filename
break
fi
done < $filename
[[ -n $hit ]] && cp /path/offblack.png $filename
done < <(find . -type -f)
Fewer man pages to search!

Add file extension to files with bash

What is the good way to add file extension ".jpg" to extension-less files with bash?
# Strip .jpg from all filenames
for f in *.jpg; do mv "$f" "${f%.jpg}"; done
# Add .jpg to all filenames (even those with .jpg already)
for f in *; do mv "$f" "$f.jpg"; done
# Add .jpg to all filenames...unless they are already .jpg
for f in *; do case "$f" in *.jpg) echo skipped $f;; *) mv "$f" "$f".jpg; esac; done
# Add .jpg to all filenames...unless they already have a . extension
for f in *; do case "$f" in *.*) echo skipped $f;; *) mv "$f" "$f".jpg; esac; done
You can use rename:
rename 's/(.*)/$1.jpg/' *
Another way - without loops
find . -type f -not -name "*.*" -print0 |\
xargs -0 file |\
grep 'JPEG image data' |\
sed 's/:.*//' |\
xargs -I % echo mv % %.jpg
Breakdown:
find all files without extension
check the file type
filter out only JPG files
delete filetype info
xargs run the "mv" for each file
the above command is for dry run, after it you should remove the "echo" before mv
EDIT
Some people suggesting that here is needed "Wrap path arguments in quotes; avoids argument splitting on paths with spaces".
Usually, this recommendation is true, in this case isn't. Because, here the % is got replaced not by shell expansion but by the xargs internally (directly), so the % will be substituted correctly even with spaces in filenames.
Simple demo:
$ mkdir xargstest
$ cd xargstest
# create two files with spaces in names
$ touch 'a b' 'c d'
$ find . -type f -print
./c d
./a b
# notice, here are spaces in the above paths
#the actual xargs mv WITHOUT quotes
$ find . -type f -print | xargs -I % mv % %.ext
$ find . -type f -print
./a b.ext
./c d.ext
# the result is correct even in case with spaces in the filenames...
Simple,
cd to the directory where your files are and:
for f in *;do mv $f $f.jpg;done
dry run:
rename -n s/$/.jpg/ *
actual renaming:
rename s/$/.jpg/ *
find . | while read FILE; do if [ $(file --mime-type -b "$FILE") == "image/jpeg" ]; then mv "$FILE" "$FILE".jpg; fi; done;
In my case i was not aware of the filetype so i used the mv command with the help of the file command to examine and possibly find the file type. This solution might not be perfect for all files since the file command might not recognize the filetype but it worked mostly good for me.
for f in *; do ext=$(file $f | awk '{print $2;}'); mv -n "$f" "$f.$ext"; done
The use of awk is to strip the second word of the string returned from the command file that is actually the extension.
rename --dry-run * -a ".jpg" # test
* -a ".jpg" # rename
You can use move multiple files. I am a maintainer of this project. The syntax is simple.
mmf files*
It will open your $EDITOR with all files names, or vim by default and you can simply highlight the end of all file names using Ctrl+v+G in vim , save the file,quit and that it , all your files are renamed
Ryan Li
The correct syntax for adding a file extension to multiple files within a directory which do not have a file extension is
find . | while read FILE; do if [[ -n `file --mime-type "$FILE" | grep 'message/rfc822'` ]]; then mv "$FILE" "$FILE".eml; fi; done;

How do I rename all folders and files to lowercase on Linux?

I have to rename a complete folder tree recursively so that no uppercase letter appears anywhere (it's C++ source code, but that shouldn't matter).
Bonus points for ignoring CVS and Subversion version control files/folders. The preferred way would be a shell script, since a shell should be available on any Linux box.
There were some valid arguments about details of the file renaming.
I think files with the same lowercase names should be overwritten; it's the user's problem. When checked out on a case-ignoring file system, it would overwrite the first one with the latter, too.
I would consider A-Z characters and transform them to a-z, everything else is just calling for problems (at least with source code).
The script would be needed to run a build on a Linux system, so I think changes to CVS or Subversion version control files should be omitted. After all, it's just a scratch checkout. Maybe an "export" is more appropriate.
Smaller still I quite like:
rename 'y/A-Z/a-z/' *
On case insensitive filesystems such as OS X's HFS+, you will want to add the -f flag:
rename -f 'y/A-Z/a-z/' *
A concise version using the "rename" command:
find my_root_dir -depth -exec rename 's/(.*)\/([^\/]*)/$1\/\L$2/' {} \;
This avoids problems with directories being renamed before files and trying to move files into non-existing directories (e.g. "A/A" into "a/a").
Or, a more verbose version without using "rename".
for SRC in `find my_root_dir -depth`
do
DST=`dirname "${SRC}"`/`basename "${SRC}" | tr '[A-Z]' '[a-z]'`
if [ "${SRC}" != "${DST}" ]
then
[ ! -e "${DST}" ] && mv -T "${SRC}" "${DST}" || echo "${SRC} was not renamed"
fi
done
P.S.
The latter allows more flexibility with the move command (for example, "svn mv").
for f in `find`; do mv -v "$f" "`echo $f | tr '[A-Z]' '[a-z]'`"; done
Just simply try the following if you don't need to care about efficiency.
zip -r foo.zip foo/*
unzip -LL foo.zip
One can simply use the following which is less complicated:
rename 'y/A-Z/a-z/' *
This works on CentOS/Red Hat Linux or other distributions without the rename Perl script:
for i in $( ls | grep [A-Z] ); do mv -i "$i" "`echo $i | tr 'A-Z' 'a-z'`"; done
Source: Rename all file names from uppercase to lowercase characters
(In some distributions the default rename command comes from util-linux, and that is a different, incompatible tool.)
This works if you already have or set up the rename command (e.g. through brew install in Mac):
rename --lower-case --force somedir/*
The simplest approach I found on Mac OS X was to use the rename package from http://plasmasturm.org/code/rename/:
brew install rename
rename --force --lower-case --nows *
--force Rename even when a file with the destination name already exists.
--lower-case Convert file names to all lower case.
--nows Replace all sequences of whitespace in the filename with single underscore characters.
Most of the answers above are dangerous, because they do not deal with names containing odd characters. Your safest bet for this kind of thing is to use find's -print0 option, which will terminate filenames with ASCII NUL instead of \n.
Here is a script, which only alter files and not directory names so as not to confuse find:
find . -type f -print0 | xargs -0n 1 bash -c \
's=$(dirname "$0")/$(basename "$0");
d=$(dirname "$0")/$(basename "$0"|tr "[A-Z]" "[a-z]"); mv -f "$s" "$d"'
I tested it, and it works with filenames containing spaces, all kinds of quotes, etc. This is important because if you run, as root, one of those other scripts on a tree that includes the file created by
touch \;\ echo\ hacker::0:0:hacker:\$\'\057\'root:\$\'\057\'bin\$\'\057\'bash
... well guess what ...
Here's my suboptimal solution, using a Bash shell script:
#!/bin/bash
# First, rename all folders
for f in `find . -depth ! -name CVS -type d`; do
g=`dirname "$f"`/`basename "$f" | tr '[A-Z]' '[a-z]'`
if [ "xxx$f" != "xxx$g" ]; then
echo "Renaming folder $f"
mv -f "$f" "$g"
fi
done
# Now, rename all files
for f in `find . ! -type d`; do
g=`dirname "$f"`/`basename "$f" | tr '[A-Z]' '[a-z]'`
if [ "xxx$f" != "xxx$g" ]; then
echo "Renaming file $f"
mv -f "$f" "$g"
fi
done
Folders are all renamed correctly, and mv isn't asking questions when permissions don't match, and CVS folders are not renamed (CVS control files inside that folder are still renamed, unfortunately).
Since "find -depth" and "find | sort -r" both return the folder list in a usable order for renaming, I preferred using "-depth" for searching folders.
One-liner:
for F in K*; do NEWNAME=$(echo "$F" | tr '[:upper:]' '[:lower:]'); mv "$F" "$NEWNAME"; done
Or even:
for F in K*; do mv "$F" "${F,,}"; done
Note that this will convert only files/directories starting with letter K, so adjust accordingly.
The original question asked for ignoring SVN and CVS directories, which can be done by adding -prune to the find command. E.g to ignore CVS:
find . -name CVS -prune -o -exec mv '{}' `echo {} | tr '[A-Z]' '[a-z]'` \; -print
[edit] I tried this out, and embedding the lower-case translation inside the find didn't work for reasons I don't actually understand. So, amend this to:
$> cat > tolower
#!/bin/bash
mv $1 `echo $1 | tr '[:upper:]' '[:lower:]'`
^D
$> chmod u+x tolower
$> find . -name CVS -prune -o -exec tolower '{}' \;
Ian
Not portable, Zsh only, but pretty concise.
First, make sure zmv is loaded.
autoload -U zmv
Also, make sure extendedglob is on:
setopt extendedglob
Then use:
zmv '(**/)(*)~CVS~**/CVS' '${1}${(L)2}'
To recursively lowercase files and directories where the name is not CVS.
Using Larry Wall's filename fixer:
$op = shift or die $help;
chomp(#ARGV = <STDIN>) unless #ARGV;
for (#ARGV) {
$was = $_;
eval $op;
die $# if $#;
rename($was,$_) unless $was eq $_;
}
It's as simple as
find | fix 'tr/A-Z/a-z/'
(where fix is of course the script above)
for f in `find -depth`; do mv ${f} ${f,,} ; done
find -depth prints each file and directory, with a directory's contents printed before the directory itself. ${f,,} lowercases the file name.
This works nicely on macOS too:
ruby -e "Dir['*'].each { |p| File.rename(p, p.downcase) }"
This is a small shell script that does what you requested:
root_directory="${1?-please specify parent directory}"
do_it () {
awk '{ lc= tolower($0); if (lc != $0) print "mv \"" $0 "\" \"" lc "\"" }' | sh
}
# first the folders
find "$root_directory" -depth -type d | do_it
find "$root_directory" ! -type d | do_it
Note the -depth action in the first find.
Use typeset:
typeset -l new # Always lowercase
find $topPoint | # Not using xargs to make this more readable
while read old
do new="$old" # $new is a lowercase version of $old
mv "$old" "$new" # Quotes for those annoying embedded spaces
done
On Windows, emulations, like Git Bash, may fail because Windows isn't case-sensitive under the hood. For those, add a step that mv's the file to another name first, like "$old.tmp", and then to $new.
With MacOS,
Install the rename package,
brew install rename
Use,
find . -iname "*.py" -type f | xargs -I% rename -c -f "%"
This command find all the files with a *.py extension and converts the filenames to lower case.
`f` - forces a rename
For example,
$ find . -iname "*.py" -type f
./sample/Sample_File.py
./sample_file.py
$ find . -iname "*.py" -type f | xargs -I% rename -c -f "%"
$ find . -iname "*.py" -type f
./sample/sample_file.py
./sample_file.py
Lengthy But "Works With No Surprises & No Installations"
This script handles filenames with spaces, quotes, other unusual characters and Unicode, works on case insensitive filesystems and most Unix-y environments that have bash and awk installed (i.e. almost all). It also reports collisions if any (leaving the filename in uppercase) and of course renames both files & directories and works recursively. Finally it's highly adaptable: you can tweak the find command to target the files/dirs you wish and you can tweak awk to do other name manipulations. Note that by "handles Unicode" I mean that it will indeed convert their case (not ignore them like answers that use tr).
# adapt the following command _IF_ you want to deal with specific files/dirs
find . -depth -mindepth 1 -exec bash -c '
for file do
# adapt the awk command if you wish to rename to something other than lowercase
newname=$(dirname "$file")/$(basename "$file" | awk "{print tolower(\$0)}")
if [ "$file" != "$newname" ] ; then
# the extra step with the temp filename is for case-insensitive filesystems
if [ ! -e "$newname" ] && [ ! -e "$newname.lcrnm.tmp" ] ; then
mv -T "$file" "$newname.lcrnm.tmp" && mv -T "$newname.lcrnm.tmp" "$newname"
else
echo "ERROR: Name already exists: $newname"
fi
fi
done
' sh {} +
References
My script is based on these excellent answers:
https://unix.stackexchange.com/questions/9496/looping-through-files-with-spaces-in-the-names
How to convert a string to lower case in Bash?
In OS X, mv -f shows "same file" error, so I rename twice:
for i in `find . -name "*" -type f |grep -e "[A-Z]"`; do j=`echo $i | tr '[A-Z]' '[a-z]' | sed s/\-1$//`; mv $i $i-1; mv $i-1 $j; done
I needed to do this on a Cygwin setup on Windows 7 and found that I got syntax errors with the suggestions from above that I tried (though I may have missed a working option). However, this solution straight from Ubuntu forums worked out of the can :-)
ls | while read upName; do loName=`echo "${upName}" | tr '[:upper:]' '[:lower:]'`; mv "$upName" "$loName"; done
(NB: I had previously replaced whitespace with underscores using:
for f in *\ *; do mv "$f" "${f// /_}"; done
)
Slugify Rename (regex)
It is not exactly what the OP asked for, but what I was hoping to find on this page:
A "slugify" version for renaming files so they are similar to URLs (i.e. only include alphanumeric, dots, and dashes):
rename "s/[^a-zA-Z0-9\.]+/-/g" filename
I would reach for Python in this situation, to avoid optimistically assuming paths without spaces or slashes. I've also found that python2 tends to be installed in more places than rename.
#!/usr/bin/env python2
import sys, os
def rename_dir(directory):
print('DEBUG: rename('+directory+')')
# Rename current directory if needed
os.rename(directory, directory.lower())
directory = directory.lower()
# Rename children
for fn in os.listdir(directory):
path = os.path.join(directory, fn)
os.rename(path, path.lower())
path = path.lower()
# Rename children within, if this child is a directory
if os.path.isdir(path):
rename_dir(path)
# Run program, using the first argument passed to this Python script as the name of the folder
rename_dir(sys.argv[1])
If you use Arch Linux, you can install rename) package from AUR that provides the renamexm command as /usr/bin/renamexm executable and a manual page along with it.
It is a really powerful tool to quickly rename files and directories.
Convert to lowercase
rename -l Developers.mp3 # or --lowcase
Convert to UPPER case
rename -u developers.mp3 # or --upcase, long option
Other options
-R --recursive # directory and its children
-t --test # Dry run, output but don't rename
-o --owner # Change file owner as well to user specified
-v --verbose # Output what file is renamed and its new name
-s/str/str2 # Substitute string on pattern
--yes # Confirm all actions
You can fetch the sample Developers.mp3 file from here, if needed ;)
None of the solutions here worked for me because I was on a system that didn't have access to the perl rename script, plus some of the files included spaces. However, I found a variant that works:
find . -depth -exec sh -c '
t=${0%/*}/$(printf %s "${0##*/}" | tr "[:upper:]" "[:lower:]");
[ "$t" = "$0" ] || mv -i "$0" "$t"
' {} \;
Credit goes to "Gilles 'SO- stop being evil'", see this answer on the similar question "change entire directory tree to lower-case names" on the Unix & Linux StackExchange.
I believe the one-liners can be simplified:
for f in **/*; do mv "$f" "${f:l}"; done
( find YOURDIR -type d | sort -r;
find yourdir -type f ) |
grep -v /CVS | grep -v /SVN |
while read f; do mv -v $f `echo $f | tr '[A-Z]' '[a-z]'`; done
First rename the directories bottom up sort -r (where -depth is not available), then the files.
Then grep -v /CVS instead of find ...-prune because it's simpler.
For large directories, for f in ... can overflow some shell buffers.
Use find ... | while read to avoid that.
And yes, this will clobber files which differ only in case...
find . -depth -name '*[A-Z]*'|sed -n 's/\(.*\/\)\(.*\)/mv -n -v -T \1\2 \1\L\2/p'|sh
I haven't tried the more elaborate scripts mentioned here, but none of the single commandline versions worked for me on my Synology NAS. rename is not available, and many of the variations of find fail because it seems to stick to the older name of the already renamed path (eg, if it finds ./FOO followed by ./FOO/BAR, renaming ./FOO to ./foo will still continue to list ./FOO/BAR even though that path is no longer valid). Above command worked for me without any issues.
What follows is an explanation of each part of the command:
find . -depth -name '*[A-Z]*'
This will find any file from the current directory (change . to whatever directory you want to process), using a depth-first search (eg., it will list ./foo/bar before ./foo), but only for files that contain an uppercase character. The -name filter only applies to the base file name, not the full path. So this will list ./FOO/BAR but not ./FOO/bar. This is ok, as we don't want to rename ./FOO/bar. We want to rename ./FOO though, but that one is listed later on (this is why -depth is important).
This comand in itself is particularly useful to finding the files that you want to rename in the first place. Use this after the complete rename command to search for files that still haven't been replaced because of file name collisions or errors.
sed -n 's/\(.*\/\)\(.*\)/mv -n -v -T \1\2 \1\L\2/p'
This part reads the files outputted by find and formats them in a mv command using a regular expression. The -n option stops sed from printing the input, and the p command in the search-and-replace regex outputs the replaced text.
The regex itself consists of two captures: the part up until the last / (which is the directory of the file), and the filename itself. The directory is left intact, but the filename is transformed to lowercase. So, if find outputs ./FOO/BAR, it will become mv -n -v -T ./FOO/BAR ./FOO/bar. The -n option of mv makes sure existing lowercase files are not overwritten. The -v option makes mv output every change that it makes (or doesn't make - if ./FOO/bar already exists, it outputs something like ./FOO/BAR -> ./FOO/BAR, noting that no change has been made). The -T is very important here - it treats the target file as a directory. This will make sure that ./FOO/BAR isn't moved into ./FOO/bar if that directory happens to exist.
Use this together with find to generate a list of commands that will be executed (handy to verify what will be done without actually doing it)
sh
This pretty self-explanatory. It routes all the generated mv commands to the shell interpreter. You can replace it with bash or any shell of your liking.
Using bash, without rename:
find . -exec bash -c 'mv $0 ${0,,}' {} \;

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