Command Line Arguments also support some really useful optional syntax to run quasi-macros on command line arguments that are file paths.
These macros are called variable substitution support and can resolve the path, timestamp, or size of file that is a command line argument. I use this trick in nearly every batch file I write to determine where the script file itself lives. I also use this trick frequently to determine the name of the script at runtime. The prefixing helps the end user by knowing the output is from the script and not another program being called by the script. It may sound silly until you spend hours trying to track down an obtuse error message generated by a script.
Trust me, you want command processor extensions. I use this variable to make fully qualified filepaths to any other files in the same directory as our script. You can also redirect the output of a command to a temporary file, and then put the contents of that temporary file into your variable, likesuchashereby.
It doesn't work with multiline input though. To add to a file,like a logger program, First make a file with a single enter key in it called e. These answers were all so close to the answer that I needed. This is an attempt to expand on them. If you're running from within a. Since the command includes colons, quotes, and parentheses, you need to include the USEBACKQ line in the options so that you can use backquotes to specify the command to run and then all kinds of funny characters inside of it.
If you don't want to output to a temp file and then read into a variable, this code stores result of command direct into a variable:. This is cleaner alternative to delims , tokens or usebackq in for loop. Another method is to set errorlevel variable, although many would discourage setting errorlevel on large scripts or when new to cmd flavor of the installed OS variant.
Above method can be modified to return encoded strings to be decoded in parent process within 32 bit limitation. A 3rd illustration, although of limited use because the variable is set in child process, not parent is:.
For command processing FOR command has two forms depending if the usebackq option is used. In the all examples below the whole output is used without splitting it. The two forms can be useful in case when you are dealing with arguments containing specific quotes. Though in both cases the expression can be put in double quotes and it still be processed. Here's an example with python it is possible to transition the expression in the brackets on a separate line which is used for easier reading :.
Though this is suitable only for straight forward scenarios. DOSKEY does accept double quotes as enclosion for arguments so this also is useful for more simple scenarios. FOR also works well with pipes which can be used for chaining commands though it is not so good for assigning a variable. And for completnes macros for the temp file approach no doskey definition ,but it also can be easy done.
Actually the original seems to be How do I get the result of a command in a variable in windows? Add a comment. Active Oldest Votes. A method has already been devised, however this way you don't need a temp file. Not sure why. Using the statement in a batch file, if command has a pipe then it errors out with: " was unexpected at this time. Anyone an idea how to preserve or obtain this?
If you're trying to catch the error value, u need to redirect it to standard out in your command section. This post has a method to achieve this from zvrba You can do it by redirecting the output to a file first. Community Bot 1 1 1 silver badge. Ian Kenney Ian Kenney 5, 1 1 gold badge 23 23 silver badges 42 42 bronze badges. ElektroStudios ElektroStudios You may delete them all and just put some echo off at the first line is really dislike that.
However like this I find debugging much more nice. But, I instead suggest using Cygwin on your Windows system if you are used to Unix-type scripting. In the Unix shell version, the assignment to "theValue" still occurs, any previous value being replaced with an empty value.
In the Windows batch version, it's the "for" command which handles the error, and the "do" clause is never reached -- so any previous value of "theValue" will be retained. To get more Unix-like semantics in Windows batch script, you must ensure that assignment takes place:. Failing to clear the variable's value when converting a Unix script to Windows batch can be a cause of subtle errors.
I've put them only for macro enclosing. It is put there as it reminds a comment and to further enhance where the macro definitions are assigned. The first takes the output of a command and redirects it ot a file.
The text between two macros is the name of the variable. Probably can be done in a more elegant way. Official Microsoft docs for for command. How are we doing? Please help us improve Stack Overflow. Take our short survey.
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