Question

I am starting with a file containing a list of hundreds of files (full paths) in a random order. I would like to list the details of the ten latest files in that list. This is my naive attempt:

$ ls -las -t `cat list-of-files.txt` | head -10

That works, so long as none of the files have spaces in, but fails if they do as those files are split up at the spaces and treated as separate files. File "hello world" gives me:

ls: hello: No such file or directory
ls: world: No such file or directory

I have tried quoting the files in the original list-of-files file, but the here-document still splits the files up at the spaces in the filenames, treating the quotes as part of the filenames:

$ ls -las -t `awk '{print "\"" $0 "\""}' list-of-files.txt` | head -10

ls: "hello: No such file or directory
ls: world": No such file or directory

The only way I can think of doing this, is to ls each file individually (using xargs perhaps) and create an intermediate file with the file listings and the date in a sortable order as the first field in each line, then sort that intermediate file. However, that feels a bit cumbersome and inefficient (hundreds of ls commands rather than one or two). But that may be the only way to do it?

Is there any way to pass "ls" a list of files to process, where those files could contain spaces - it seems like it should be simple, but I'm stumped.

Was it helpful?

Solution

Instead of "one or more blank characters", you can force bash to use another field separator:

OIFS=$IFS
IFS=$'\n'

ls -las -t $(cat list-of-files.txt) | head -10
IFS=$OIFS

However, I don't think this code would be more efficient than doing a loop; in addition, that won't work if the number of files in list-of-files.txt exceeds the max number of arguments.

OTHER TIPS

Try this:

xargs -a list-of-files.txt ls -last | head -n 10

I'm not sure whether this will work, but did you try escaping spaces with \? Using sed or something. sed "s/ /\\\\ /g" list-of-files.txt, for example.

This worked for me:

xargs -d\\n ls -last < list-of-files.txt | head -10
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