How do I redirect command output to a file?

Question

I have a command that I run in a folder that outputs MD5 hashes and filenames on the terminal:

ls |sort -nr | xargs md5sum

I need this output in a text file that I can download and compare to another folder on another customer's machine. How can I modify the command such that its output is stored in a file in say /tmp? I'm using Redhat 5.

Answer 1

It's a bad idea to parse the output of ls. The primary job of ls is to list the attributes of files (size, date, etc.). The shell itself is perfectly capable of listing the contents of a directory, with wildcards.

It's quite simple to run md5sum on all the files in the current directory and put the output in a file: redirect its output to the desired output file.

md5sum * >/tmp/md5sums.txt

If you want the output to be sorted by file name, pipe the output of md5sum into sort.

md5sum * | sort -k 2 >/tmp/md5sums.txt

Note that numeric sorting (-n) will only give useful results if the file names are purely numeric. If all you need is for the output to be deterministic, how you sort doesn't matter.

Answer 2

output redirecting is done by below command

commandname > filename

Answer 3

Same way as on most non-*nix platforms, actually.

somecommand > somefile

You don't need to sort it though, as md5sum -c will check the files for you.