RENAME using redirection operators......

[atamo]

Hy

I want to rename a file with a name from a text file, e.g.

Code: Select all

ren old.rar < newname.txt
where newname.txt contain a single line:  new.rar

I get syntax error

if I use

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for /f %i in (c:\newname.txt) do ren c:\old.rar %i

work fine ... but why can't I use redirection operators, Which is the good syntax

[dbenham]

Because command (program) command line arguments are not the same thing as command (program) input (also known as stdin, or standard input).

From an English language perspective, yes they are both forms of input to the program. But from a programming standpoint they are very different.

The < operator is providing data for standard input, but the ren command does not make use of the input. It requires two arguments, source and destination.

A few commands allow such operations, but they are not the norm. For example:

findstr xyz file.txt
and
findstr xyz < file.txt

will yield the same results, but that is only because the developer of the command went to extra effort to add that capability. It does not happen automatically.

[atamo]

Thank's the meticulous explain

It requires two arguments, source and destination.

unfortunately the next code also don't work:

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ren < newname.txt
where newname.txt contain a single line with two parameters: old.rar new.rar