[linux] How can I use xargs to copy files that have spaces and quotes in their names?

I'm trying to copy a bunch of files below a directory and a number of the files have spaces and single-quotes in their names. When I try to string together find and grep with xargs, I get the following error:

find .|grep "FooBar"|xargs -I{} cp "{}" ~/foo/bar
xargs: unterminated quote

Any suggestions for a more robust usage of xargs?

This is on Mac OS X 10.5.3 (Leopard) with BSD xargs.

With Bash (not POSIX) you can use process substitution to get the current line inside a variable. This enables you to use quotes to escape special characters:

while read line ; do cp "$line" ~/bar ; done < <(find . | grep foo)

This is more efficient as it does not run "cp" multiple times:

find -name '*FooBar*' -print0 | xargs -0 cp -t ~/foo/bar

The easiest way to do what the original poster wants is to change the delimiter from any whitespace to just the end-of-line character like this:

find whatever ... | xargs -d "\n" cp -t /var/tmp

find . -print0 | grep --null 'FooBar' | xargs -0 ...

I don't know about whether grep supports --null, nor whether xargs supports -0, on Leopard, but on GNU it's all good.

Just don't use xargs. It is a neat program but it doesn't go well with find when faced with non trivial cases.

Here is a portable (POSIX) solution, i.e. one that doesn't require find, xargs or cp GNU specific extensions:

find . -name "*FooBar*" -exec sh -c 'cp -- "$@" ~/foo/bar' sh {} +

Note the ending + instead of the more usual ;.

This solution:

• correctly handles files and directories with embedded spaces, newlines or whatever exotic characters.

• works on any Unix and Linux system, even those not providing the GNU toolkit.

• doesn't use xargs which is a nice and useful program, but requires too much tweaking and non standard features to properly handle find output.

• is also more efficient (read faster) than the accepted and most if not all of the other answers.

Note also that despite what is stated in some other replies or comments quoting {} is useless (unless you are using the exotic fishshell).

I played with this a little, started contemplating modifying xargs, and realised that for the kind of use case we're talking about here, a simple reimplementation in Python is a better idea.

For one thing, having ~80 lines of code for the whole thing means it is easy to figure out what is going on, and if different behaviour is required, you can just hack it into a new script in less time than it takes to get a reply on somewhere like Stack Overflow.

See https://github.com/johnallsup/jda-misc-scripts/blob/master/yargs and https://github.com/johnallsup/jda-misc-scripts/blob/master/zargs.py.

With yargs as written (and Python 3 installed) you can type:

find .|grep "FooBar"|yargs -l 203 cp --after ~/foo/bar

to do the copying 203 files at a time. (Here 203 is just a placeholder, of course, and using a strange number like 203 makes it clear that this number has no other significance.)

If you really want something faster and without the need for Python, take zargs and yargs as prototypes and rewrite in C++ or C.

If you are using Bash, you can convert stdout to an array of lines by mapfile:

find . | grep "FooBar" | (mapfile -t; cp "${MAPFILE[@]}" ~/foobar)

The benefits are:

• It's built-in, so it's faster.
• Execute the command with all file names in one time, so it's faster.

• You can append other arguments to the file names. For cp, you can also:

  find . -name '*FooBar*' -exec cp -t ~/foobar -- {} +
  

  however, some commands don't have such feature.

The disadvantages:

• Maybe not scale well if there are too many file names. (The limit? I don't know, but I had tested with 10 MB list file which includes 10000+ file names with no problem, under Debian)

Well... who knows if Bash is available on OS X?

Frame challenge — you're asking how to use xargs. The answer is: you don't use xargs, because you don't need it.

The comment by user80168 describes a way to do this directly with cp, without calling cp for every file:

find . -name '*FooBar*' -exec cp -t /tmp -- {} +

This works because:

• the cp -t flag allows to give the target directory near the beginning of cp, rather than near the end. From man cp:

   -t, --target-directory=DIRECTORY
         copy all SOURCE arguments into DIRECTORY

• The -- flag tells cp to interpret everything after as a filename, not a flag, so files starting with - or -- do not confuse cp; you still need this because the -/-- characters are interpreted by cp, whereas any other special characters are interpreted by the shell.

• The find -exec command {} + variant essentially does the same as xargs. From man find:

   -exec command {} +                                                     
         This  variant  of the -exec action runs the specified command on
         the selected files, but the command line is built  by  appending
         each  selected file name at the end; the total number of invoca-
         matched  files.   The command line is built in much the same way
         that xargs builds its command lines.  Only one instance of  `{}'
         is  allowed  within the command, and (when find is being invoked
         from a shell) it should be quoted (for example, '{}') to protect
         it  from  interpretation  by shells.  The command is executed in
         the starting directory.  If any invocation  returns  a  non-zero
         value  as exit status, then find returns a non-zero exit status.
         If find encounters an error, this can sometimes cause an immedi-
         ate  exit, so some pending commands may not be run at all.  This
         variant of -exec always returns true.

By using this in find directly, this avoids the need of a pipe or a shell invocation, such that you don't need to worry about any nasty characters in filenames.

I created a small portable wrapper script called "xargsL" around "xargs" which addresses most of the problems.

Contrary to xargs, xargsL accepts one pathname per line. The pathnames may contain any character except (obviously) newline or NUL bytes.

No quoting is allowed or supported in the file list - your file names may contain all sorts of whitespace, backslashes, backticks, shell wildcard characters and the like - xargsL will process them as literal characters, no harm done.

As an added bonus feature, xargsL will not run the command once if there is no input!

Note the difference:

$ true | xargs echo no data
no data

$ true | xargsL echo no data # No output

Any arguments given to xargsL will be passed through to xargs.

Here is the "xargsL" POSIX shell script:

#! /bin/sh
# Line-based version of "xargs" (one pathname per line which may contain any
# amount of whitespace except for newlines) with the added bonus feature that
# it will not execute the command if the input file is empty.
#
# Version 2018.76.3
#
# Copyright (c) 2018 Guenther Brunthaler. All rights reserved.
#
# This script is free software.
# Distribution is permitted under the terms of the GPLv3.

set -e
trap 'test $? = 0 || echo "$0 failed!" >& 2' 0

if IFS= read -r first
then
        {
                printf '%s\n' "$first"
                cat
        } | sed 's/./\\&/g' | xargs ${1+"$@"}
fi

Put the script into some directory in your $PATH and don't forget to

$ chmod +x xargsL

the script there to make it executable.

If find and xarg versions on your system doesn't support -print0 and -0 switches (for example AIX find and xargs) you can use this terribly looking code:

 find . -name "*foo*" | sed -e "s/'/\\\'/g" -e 's/"/\\"/g' -e 's/ /\\ /g' | xargs cp /your/dest

Here sed will take care of escaping the spaces and quotes for xargs.

Tested on AIX 5.3

This method works on Mac OS X v10.7.5 (Lion):

find . | grep FooBar | xargs -I{} cp {} ~/foo/bar

I also tested the exact syntax you posted. That also worked fine on 10.7.5.

I have found that the following syntax works well for me.

find /usr/pcapps/ -mount -type f -size +1000000c | perl -lpe ' s{ }{\\ }g ' | xargs ls -l | sort +4nr | head -200

In this example, I am looking for the largest 200 files over 1,000,000 bytes in the filesystem mounted at "/usr/pcapps".

The Perl line-liner between "find" and "xargs" escapes/quotes each blank so "xargs" passes any filename with embedded blanks to "ls" as a single argument.

You might need to grep Foobar directory like:

find . -name "file.ext"| grep "FooBar" | xargs -i cp -p "{}" .

For me, I was trying to do something a little different. I wanted to copy my .txt files into my tmp folder. The .txt filenames contain spaces and apostrophe characters. This worked on my Mac.

$ find . -type f -name '*.txt' | sed 's/'"'"'/\'"'"'/g' | sed 's/.*/"&"/'  | xargs -I{} cp -v {} ./tmp/

I used Bill Star's answer slightly modified on Solaris:

find . -mtime +2 | perl -pe 's{^}{\"};s{$}{\"}' > ~/output.file

This will put quotes around each line. I didn't use the '-l' option although it probably would help.

The file list I was going though might have '-', but not newlines. I haven't used the output file with any other commands as I want to review what was found before I just start massively deleting them via xargs.

find | perl -lne 'print quotemeta' | xargs ls -d

I believe that this will work reliably for any character except line-feed (and I suspect that if you've got line-feeds in your filenames, then you've got worse problems than this). It doesn't require GNU findutils, just Perl, so it should work pretty-much anywhere.

Be aware that most of the options discussed in other answers are not standard on platforms that do not use the GNU utilities (Solaris, AIX, HP-UX, for instance). See the POSIX specification for 'standard' xargs behaviour.

I also find the behaviour of xargs whereby it runs the command at least once, even with no input, to be a nuisance.

I wrote my own private version of xargs (xargl) to deal with the problems of spaces in names (only newlines separate - though the 'find ... -print0' and 'xargs -0' combination is pretty neat given that file names cannot contain ASCII NUL '\0' characters. My xargl isn't as complete as it would need to be to be worth publishing - especially since GNU has facilities that are at least as good.

Look into using the --null commandline option for xargs with the -print0 option in find.

I ran into the same problem. Here's how I solved it:

find . -name '*FoooBar*' | sed 's/.*/"&"/' | xargs cp ~/foo/bar

I used sed to substitute each line of input with the same line, but surrounded by double quotes. From the sed man page, "...An ampersand (``&'') appearing in the replacement is replaced by the string matching the RE..." -- in this case, .*, the entire line.

This solves the xargs: unterminated quote error.

bill_starr's Perl version won't work well for embedded newlines (only copes with spaces). For those on e.g. Solaris where you don't have the GNU tools, a more complete version might be (using sed)...

find -type f | sed 's/./\\&/g' | xargs grep string_to_find

adjust the find and grep arguments or other commands as you require, but the sed will fix your embedded newlines/spaces/tabs.

For those who relies on commands, other than find, eg ls:

find . | grep "FooBar" | tr \\n \\0 | xargs -0 -I{} cp "{}" ~/foo/bar