If start is less than end the command will execute. When the iterative variable exceeds end , the command shell exits the loop. You can also use a negative step to step through a range in decreasing values.
For example, 1,1,5 generates the sequence 1 2 3 4 5 and 5,-1,1 generates the sequence 5 4 3 2 1. Iterating and file parsing: Use file parsing to process command output, strings, and file content.
Use iterative variables to define the content or strings that you want to examine, and use the various parsingkeywords options to further modify the parsing.
Use the parsingkeywords token option to specify which tokens should be passed as iterative variables. File parsing consists of reading the output, string, or file content, and then breaking it into individual lines of text and parsing each line into zero or more tokens.
The for loop is then called with the iterative variable value set to the token. Blank lines are skipped. The set argument specifies one or more file names. Each file is opened, read, and processed before moving to the next file in set. To override the default parsing behavior, specify parsingkeywords. This is a quoted string that contains one or more keywords to specify different parsing options. Variable substitution: The following table lists optional syntax for any variable I :.
It is treated as a command line, which is passed to a child Cmd. The output is captured into memory and parsed as if it is a file. To display the contents of all the files in the current directory that have the extension. You can run them in the normal File Explorer, or you can launch them from the command line of the Command Prompt. Command Line Arguments Batch scripts support the concept of command line arguments wherein arguments can be passed to the batch file when invoked.
If the above batch script is stored in a file called test. The above command produces the following output. Bat File Parameter If we were to run the batch as The output would still remain the same as above. However, the fourth parameter would be ignored. Syntax where, variable-name is the name of the variable you want to set. The following example shows a simple way the set command can be used. Example In the above code snippet, a variable called message is defined and set with the value of 'Hello World'.
Output The above command produces the following output. Working with Numeric Values In batch script, it is also possible to define a variable to hold a numeric value.
We are first setting the value of 2 variables, a and b to 5 and 10 respectively. The "script" in this context being a line - or block - of code, surrounded by round brackets:.
In the above example, the ECHO command is evaluated as Hello when the script is read into memory, so the script will echo Hello forever, however many passes are made through the script. The way to achieve the more "traditional" variable behaviour of the variable being expanded whilst the script is running is to enable "delayed expansion".
This involves adding that command into the script prior to the loop instruction usually a FOR loop, in a batch script , and using an exclamation mark! Now, an advanced technique. Using the CALL command allows the batch command processor to expand a variable located on the same line of the script.
This can deliver multilevel expansion, by repeated CALL and modifier use. This is useful in, for example, a FOR loop. As in the following example, where we have a numbered list of variables:. Note that the variable! This is double expansion of the variable i. Thus it increases to 2 on the 2nd pass through the loop, and to 3 on the 3rd pass.
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