Perform command substitution Windows command-prompt

Question

How can you perform command substitutions at the Windows command-prompt?

Command substitution is a very powerful concept of the UNIX shell. It is used to insert the output of one command into a second command. E.g. with an assignment:

$ today=$(date) # starts the "date" command, captures its output
$ echo "$today"
Mon Jul 26 13:16:02 MEST 2004

This can also be used with other commands besides assignments:

$ echo "Today is $(date +%A), it's $(date +%H:%M)"
Today is Monday, it's 13:21

This calls the date command two times, the first time to print the week-day, the second time for the current time.

I need to know to do that in the command-prompt, (I already know that there is a way to perform something like that using as part of the for command, but this way is much more obfuscated and convoluted.

Answer 1

You cannot do that in DOS.

If by DOS you mean the Windows Command Processor cmd.exe then you can get the output of a command with for /f:

for /f %%x in ('date') do set "today=%%x"

Depending on your requirements this can get a little more complex.

Answer 2

If you'd like a genuine Unix-style command substitution, not the more limited facility you get with cmd.exe, consider getting a genuine Unix shell for Windows. Two that I can suggest are Cygwin (free, but doesn't understand the Windows filesystem very well) and my own Hamilton C shell (commercial, but written for Windows).