How to use the results of "file" (Name of Creating Application: Microsoft Word) to search for a specific string?

Question

I am trying use the results of "file" which returns info about the file/s I specify.

E.g.

file *.doc 'all .doc extensions 

This then returns information about the file including "Name of Creating Application: Microsoft Word" Now, I am trying to search the results for the string "Word". I'm stuck here. How do I actually do that?

*This is what I tried after hours of searching. I just don't know what word I'm looking for. Please advise.

find . -type f -print0 | xargs -0 grep -lh "Microsoft Word" | xargs -I % mv % ../NewDirectory/ 

I think this searches for the string "Word" inside the files itself and moves it to the new directory.

Answer 1

If I understand correctly, you want to move files from the current directory and its subdirectories recursively to another directory, but only if the file command reports them as “Microsoft Word” files. That is, you're interested in the files for which file "$filename" | grep 'Microsoft Word' produces some output.

An easy way is to take things calmly and to it file by file. If you only want the files in the current directory, you can use a for loop and a wildcard pattern:

for f in *.doc; do if … done 

What's the condition? We want to test if Microsoft Word appears in the output of file "$f". I use file -- to protect against files whose name begins with -.

for f in *.doc; do if file -- "$f" | grep -s 'Microsoft Word'; then … fi done 

All we need to do is add the command to move the files.

for f in *.doc; do if file -- "$f" | grep -s 'Microsoft Word'; then mv -- "$f" ../NewDirectory/ fi done 

If you want to look for files in subdirectories as well, use the ** wilcdard pattern for recursive globbing. In bash, it needs to be activated with shopt -s globstar (in ksh93, you need set -o globstar, and in zsh it works out of the box; other shells lack this feature). Beware that bash ≤4.2 follows symbolic links to directories.

for f in **/*.doc; do if file -- "$f" | grep -s 'Microsoft Word'; then mv -- "$f" ../NewDirectory/ fi done 

Note that all moved files end in ../NewDirectory/, no subdirectories are created. If you want to reproduce the directory tree, you can use string manipulation constructs to extract the directory part of the file name and mkdir -p to create the target directory if necessary.

for f in ./**/*.doc; do if file "$f" | grep -s 'Microsoft Word'; then d="${f%/*}" mkdir -p ../NewDirectory/"$d" mv "$f" ../NewDirectory/"$d" fi done 

Rather than parse the output of file, which is somewhat fragile, you might prefer to parse file -i, which prints standardized strings.

Answer 2

Your first file example will not work because of the unmatched single quote, but I think you already found that because of your second example.

If you do:

find . -type f 

you can look at the output. Those are filenames. If you want to select something from that output use grep directly

find . -type f | grep "Microsoft Word" 

that searches through the filenames, not through the contents of the files listed. That is not completely accurate, as a filename could have a newline in them, making the output incomplete if a filename with "Microsoft Word" in it has a newline as part of the name.

If you do:

find . -type f -print0 | xargs -0 grep -lh "Microsoft Word" 

the xargs part actually hands the filenames to grep (the -print0 for find and -0 for xargs is to handle filename with newlines). This searches for the whole string "Microsoft Word" not just "Word" in the files.

The -lh specified for grep lists the filenames, and there might be a problem with that as newlines in filenames are printed normally, you should continue to use NUL terminated filenames by specifying -Z as well. If you don't specify -l you get the contents of the lines matches as well, which would make further processing (your mv) impossible.

If you want to move all the files into one directory it is often easier to use mv -t instead of mucking with xargs' -I option (which allows you to put parameters xargs reads from its input at a different place than the default end-of-line but which is slower as mv is called once for each file):

find . -type f -print0 | xargs -0 grep -lhZ "Microsoft Word" | xargs -0 mv -t ../NewDirectory/ 

And this moves all files somewhere under the current directory, with "Microsoft Word" in part of their content to the NewDirectory that is next to the current directory. Please note that ../NewDirectory has to exist.