Defining and using a variable in batch file
I'm trying to define and use a variable in a batch file. It looks like it should be simple:
@echo off
set location = "bob"
echo We're working with "%location%"
The output I get is the following:
We're working with ""
What's going on here? Why is my variable not being echo'd?
The space before the = is interpreted as part of the name, and the space after it (as well as the quotation marks) are interpreted as part of the value. So the variable you’ve created can be referenced with %location %. If that’s not what you want, remove the extra space(s) in the definition.
The spaces are significant. You created a variable named 'location ' with a value of
' "bob"'. Note - enclosing single quotes were added to show location of space.
If you want quotes in your value, then your code should look like
set location="bob"
If you don't want quotes, then your code should look like
set location=bob
Or better yet
set "location=bob"
The last syntax prevents inadvertent trailing spaces from getting in the value, and also protects against special characters like & | etc.
%, and possibly ! if delayed expansion is enabled. But if the value does contain quotes, then you must worry about when to escape poison characters like |, &, etc.
input location.bat
@echo off
cls
set /p "location"="bob"
echo We're working with %location%
pause
output
We're working with bob
(mistakes u done : space and " ")
set /p prompts the user and stores the answer in the specified variable. e.g., set /p name="What is your name? " & echo Hello, %name%.
set /p "varname"="text" is wrong, it creates a variable named location" (with a trailing quote!). It should be set /p location="bob". But even then, it doesn't match the question anymore
Consider also using SETX - it will set variable on user or machine (available for all users) level though the variable will be usable with the next opening of the cmd.exe ,so often it can be used together with SET :
::setting variable for the current user
if not defined My_Var (
set "My_Var=My_Value"
setx My_Var My_Value
)
::setting machine defined variable
if not defined Global_Var (
set "Global_Var=Global_Value"
SetX Global_Var Global_Value /m
)
You can also edit directly the registry values:
User Variables: HKEY_CURRENT_USER\Environment
System Variables: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment
Which will allow to avoid some restrictions of SET and SETX like the variables containing = in their names.
3rd party edit
SETX.exe Set environment variables permanently, SETX can be used to set Environment Variables for the machine (HKLM) or currently logged on user (HKCU):
Option /m
/m
Set the variable in the system environment HKLM.
(The default is the local environment HKCU)
Another example
::setting variable for the current user
if not defined JAVAJDK (
set "JAVAJDK=C:\Program Files\Java\jdk-13\bin"
setx JAVAJDK "C:\Program Files\Java\jdk-13\bin"
)
In a command.exe you can use the variable like this cd %JAVAJDK%.
Follow WeChat
Success story sharing
Want to stay one step ahead of the latest teleworks?
Subscribe Now相似问题
- How can I pass arguments to a batch file?
- Batch file to delete files older than N days
- Split long commands in multiple lines through Windows batch file
- Windows batch files: .bat vs .cmd?
- How to run multiple .BAT files within a .BAT file
- What does %~dp0 mean, and how does it work?
- How do I delete an exported environment variable?
- How can I auto-elevate my batch file, so that it requests from UAC administrator rights if required?
- How to "comment-out" (add comment) in a batch/cmd?
=is interpreted as part of the name then the variable cannot be referenced as%location%, it has to be referenced as%location %. Is that a typo?alias x = yin *nix land?x = y?