BASH Linux - How to pass the result of find into a mv destination via echo

Question

I have a directory which is filled with PDFS that were uploaded by a user and that didnt realize that certain naming conventions needed to be followed to have the files be downloadable again. To fix the issue en mass, I need to run a bash script or command that will recursively spider through the subdirectories and strip out the bad characters and rename the files.

I thought I had it all figured out, but alas, I am stuck on one part. Once I run my command (see below) I get a host of errors showing its finding the files, but the argument list for move (the destination) isnt being set properly. How do I pass the filename into the sub-command?

find . -name '*.pdf' -or -name '*.PDF' -execdir mv -v '{}' `echo {} | tr ' ' '_' | tr -d '[{}(),\!]' | tr -d "\'" | tr '[A-Z]' '[a-z]' | sed 's/_-_/_/g'`\;

I know my issue is the echo {} thing, but I have no idea how to get the filename found by find in there. The first substitution works, the echo one doesnt.

Thanks in advance!

Answer 1

ShellCheck helpfully points out three issues with your command:

1. Your -execdir ignores everything before the -or

2. Your \\; has to be a separate argument

3. Your `..` will expand once before find runs, not per file found.

Additionally,

• The {} in the tr is interpretted by find
• tr arguments should not have [] around them

Accounting for all this:

find . \( -name '*.pdf' -or -name '*.PDF' \) \
    -execdir sh -c 'mv -v "$1" "$(echo "$1" | tr " " "_" | tr -d "{()},\!'\''" | tr "A-Z" "a-z" | sed "s/_-_/_/g")"' _ {} \;

Answer 2

This does not work because your command substitution (delimited by the backticks) is done before the find command is executed, so {} is not yet available. I'd suggest restructuring your command by pulling out the substitutions to a loop that iterates over find 's results:

find . -print0 -name '*.pdf' -or -name '*.PDF' | 
while read -d $'\0' -r name ; do
    pushd $( dirname "$name" ) &>/dev/null
    newname=$( tr ' ' '_' <<<"$name" | 
               tr -d '[{}(),\!]' | 
               tr -d "\'" | 
               tr '[A-Z]' '[a-z]' | 
               sed 's/_-_/_/g' )
    mv "$name" "$newname"
    popd &>/dev/null
done

The find command in this example used the print0 option to separate its results with \\0 characters. read in the loop's head is instructed to ignore escape sequences ( -r ) and use the \\0 characters as delimiters ( -d ). pushd and popd are used to emulate find 's -execdir behavior that you had in your original command.

Answer 3

像这样将一个命令传递给另一个命令：

command1 | command2