Do you mean assigning value to a property from command line? If so, try

    -DpropertyName=itsValue

For example,

    &lt;project&gt;
        &lt;target name=&quot;hi&quot;&gt;
            &lt;property name=&quot;person&quot; value=&quot;world&quot;/&gt;
            &lt;echo message=&quot;Hello ${person}&quot;/&gt;
        &lt;/target&gt;
    &lt;/project&gt;

and then

    ant -Dperson=&quot;MerryPrankster&quot; hi

yields

     [echo] Hello MerryPrankster

I have been using &quot;Accelerated C++&quot; to learn C++ over the summer, and there&#39;s a concept which I don&#39;t seem to understand properly.

Why is

    int x;
    if (cin &gt;&gt; x){}

equivalent to

    cin &gt;&gt; x;
    if (cin){}

By looking at the code, it seems to me that we&#39;re using cin as a variable. But, I thought it was a function. Why can we use cin in this way when it is x that has whatever value we input into our keyboard?

if (cin &gt;&gt; x) - Why can you use that condition?

I wonder why one of my projects has `VDSERR.h` listed under &quot;External Dependencies&quot; and another hasn&#39;t and gives me an &quot;undefined symbol&quot; compiler error about a symbol which is defined in there. How can I include this file in the other project as well?

How do files get into the External Dependencies in Visual Studio C++?

I need to invoke a ant script via shell script. Let us consider the parameters for ant script are a,b,c. how can i pass the parameter for those variables? I must provide the parameters for ant vis invoke the shell script. can anyone help me on this?

How to Pass parameters for a Ant script , which is invoked via shell script?

<p>I need to invoke a ant script via shell script. Let us consider the parameters for ant script are a,b,c. how can i pass the parameter for those variables? I must provide the parameters for ant vis invoke the shell script. can anyone help me on this?</p>


I&#39;m currently building a program which adds to the current user&#39;s shell depending on the project he&#39;s working on, by defining per-project aliases and functions. These aliases and functions may and will certainly have the same name like for instance `cdproj`, which would `cd` to the project&#39;s root.

I would like to remove previously defined aliases and functions when changing project (before (re)defining aliases and functions for the other project. I know I can remove an alias with `unalias` in both bash and zsh, but how would I do the same for a function?

Remove function definition (unalias equivalent)

I&#39;m trying to learn shell scripting, and I need to understand someone else&#39;s code. What is the `$?` variable hold? I can&#39;t Google search the answer because they block punctuation characters.

What is the $? (dollar question mark) variable in shell scripting?

&gt;Write a simple script that will automatically rename a number of files. As an example we want the file *001.jpg renamed to user defined string + 001.jpg (ex: MyVacation20110725_001.jpg) The usage for this script is to get the digital camera photos to have file names that make some sense.

I need to write a shell script for this. Can someone suggest how to begin?

Rename multiple files by replacing a particular pattern in the filenames using a shell script

I want to differentiate the STDOUT and STDERR messages in my terminal.
If a script or command is printing a message in terminal I want to differentiate by colors; is it possible?

(E.g. stderr font color is red, and stdout font color is blue.)

Example (using bold):

&gt; `$date`  
&gt; `Wed Jul 27 12:36:50 IST 2011`
&gt;
&gt; `$datee`  
&gt; **`bash: datee: command not found`**
&gt;
&gt; `$alias ls`  
&gt; `alias ls=&#39;ls --color=auto -F&#39;`
&gt;
&gt; `$aliass ls`  
&gt; **`bash: aliass: command not found`**



How to set font color for STDOUT and STDERR

I know I can test for an empty string in Bash with `-z` like so:

    if [[ -z $myvar ]]; then do_stuff; fi

but I see a lot of code written like:

    if [[ X&quot;&quot; = X&quot;$myvar&quot; ]]; then do_stuff; fi

Is that method more portable? Is it just historical cruft from before the days of `-z`? Is it for POSIX shells (even though I&#39;ve seen it used in scripts targeting `bash`)? Ready for my history/portability lesson.

----------

The same question was asked on Server Fault as [How to determine if a bash variable is empty?](https://serverfault.com/questions/7503/) but no one offered an explanation as to *why* you see code with the `X&quot;&quot;` stuff.


Test for empty string with X&quot;&quot;

I&#39;m fairly proficient at writing Batch scripts for Windows, but even after all these years how to correctly escape characters puzzles me.  It&#39;s especially difficult when trying figure out the correct way to escape a regular expression for use with sed. Is there any tool that can help me?  Perhaps something that allows me to paste in a &quot;normal&quot; string and it spits out the correctly escaped version of that string?

**Update:**   I&#39;m reluctant to give an example because I&#39;m not looking for an answer on how to escape one specific string. I&#39;m also not looking for a solution that will work for one specific app. I&#39;m looking for a tool that will help me get the escape syntax correct for every string I ever need to escape no matter what tool might be consuming it from the command line.  

That being said the regex I really want is 

    (^.*)(Form Product=&quot;)([^&quot;]*&quot;) FormType=&quot;[^&quot;]*&quot; FormID=&quot;([0-9][0-9]*)&quot;.*$

Take that true regex (i.e. unescaped as far as BATCH is concerned) and wrap it in some sed syntax such as `ssed &quot;s@ --- Insert escaped regex here ---      @http://psph/\1/\2@g&quot; &quot;%~1&quot;` and finally escape it... Again, is there any tool that can assist in escaping any string for use on the BATCH command line? 


p.s. There are so many exceptions to BATCH&#39;s escaping syntax that I&#39;ll even settle for a good cheat sheet.




Batch character escaping

I have a file with about 1000 lines. I want the part of my file after the line which matches my grep statement.

That is:

    cat file | grep &#39;TERMINATE&#39;     # It is found on line 534

So, I want the file from line 535 to line 1000 for further processing.

How can I do that?



How to get the part of a file after the first line that matches a regular expression

What does 

    echo $?

mean in shell programming?

Meaning of $? (dollar question mark) in shell scripts

I&#39;m trying to use cURL in a script and get it to ***not*** show the progress bar. 

I&#39;ve tried the `-s`, `-silent`, `-S`, and `-quiet` options, but none of them work.

Here&#39;s a typical command I&#39;ve tried:

    curl -s http://google.com &gt; temp.html


I only get the progress bar when pushing it to a file, so `curl -s http://google.com` doesn&#39;t have a progress bar, but `curl -s http://google.com &gt; temp.html` does.

How do I get cURL to not show the progress bar?

After the installation of my ant in my windows 7 . In cmd i typed **ant -v** it&#39;s given the ant version but it says the following also. 

    Buildfile: build.xml does not exist!
    Build failed

What&#39;s the problem in the system. How i can rectify this issue? 

ant build.xml file doesn&#39;t exist

I am using `ant-release` to do a 1-step build of my Android app.

My build.properties looks like this:

    application.package=xxxxx
    key.store=sonr
    key.alias=sonr labs
    key.store.password=xxxx
    key.alias.password=xxxx

When I run ant-release everything is fine except for application signing. I get the error:


    -release-prompt-for-password:
    
    -release-nosign:
         [echo] No key.store and key.alias properties found in build.properties.
         [echo] Please sign /Users/syalam/Documents/git/joeborn-sonr/sonr/bin/SONR-release-unsigned.apk manually
         [echo] and run zipalign from the Android SDK tools.
    [propertyfile] Updating property file: /Users/syalam/Documents/git/joeborn-sonr/sonr/bin/build.prop
    [propertyfile] Updating property file: /Users/syalam/Documents/git/joeborn-sonr/sonr/bin/build.prop
    [propertyfile] Updating property file: /Users/syalam/Documents/git/joeborn-sonr/sonr/bin/build.prop
    [propertyfile] Updating property file: /Users/syalam/Documents/git/joeborn-sonr/sonr/bin/build.prop

How can I resolve this?

PS. I followed this tutorial for getting my build process down http://www.androidengineer.com/2010/06/using-ant-to-automate-building-android.html



No key.store and key.alias properties found in build.properties

I am trying to compile my JasperReports template using an Ant script and Java. I am getting this error:

    jasper java.lang.NoClassDefFoundError:
    org/codehaus/groovy/control/CompilationFailedException

There is nothing complex in the template, but I still can&#39;t compile.

Why do I get compilation error &quot;org/codehaus/groovy/control/CompilationFailedException&quot;?

Trying to build my project with ANT in idea 10 and I get a compile error but I don&#39;t see the actual error.
 
How do I make ANT verbose?
 
All I see is:
 

    javac build.xml:303: Compile failed; see the compiler error output for
    details. at
    org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:1150)
    etc.... rest of ANT stack trace

 
My task looks like this:
 

    &lt;javac includeantruntime=&quot;false&quot; destdir=&quot;${webapp.classes.dir}&quot; debug=&quot;true&quot;&gt;
        &lt;src path=&quot;${src.dir}&quot;/&gt;
        &lt;classpath refid=&quot;project.classpath&quot;/&gt;
    &lt;/javac&gt;


How do I make ANT verbose?

I think this question is an extension of https://stackoverflow.com/questions/7884809/compare-to-the-ide-for-java-do-we-still-need-ant

There are answers for the question above, but I wish to know a concrete example of using Maven or Ant over just Eclipse. 

When I develop in Eclipse, Eclipse does everything for me and I just need to click the run button. And also, Eclipse can let you export your code to a runnable jar or even .exe for windows.

So I really don&#39;t know why I need Maven or Ant.

And also if I do need, **which one should I choose, Maven or Ant?**

Why do we need Maven or Ant, if we already have Eclipse?

Is it possible to read the following from the local variable in Lua?

    local t = os.execute(&quot;echo &#39;test&#39;&quot;)
    print(t)

I just want to achieve this: whenever `os.execute` returns any value, I would like to use it in Lua - for example `echo &#39;test&#39;` will output `test` in the bash command line - is that possible to get the returned value (`test` in this case) to the Lua local variable?



Lua os.execute return value

Can I know what are the differences between each `Exec`, `ExecWait`, `ExecShell`, `nsExec::Exec`, `nsExec::ExecToLog,` `nsExec::ExecToStack`, `ExecDos` and `ExecCmd`, as in when to use which?

I &#39;ve posted the various execute calls I know. I am trying to make a comprehensive list, so that it helps future visitors..

1. `Exec`: Plainly execute the called string, be it some application, console or file.

2. `ExecWait`: Executes like `Exec` but waits till the process exits.

3. `ExecShell`: **What is it for?**

4. `nsExec::Exec`: Just like `Exec` or `ExecWait` but only for command prompt and that too without opening the console window. I am unsure if it waits for process to exit. **Does `nsExec::Exec` wait for child process to exit?**

5. `nsExec::ExecToLog`: `The documentation says ExecToLog` is similar to plain `nsExec` but it outputs to log window. **What does that mean, what is a log window?**

6. `nsExec::ExecToStack`: The documentation says `ExecToStack` is similar to plain `nsExec` but it pushes output to stack. I get that.

7. `ExecDos`: Same as `nsExec::ExecToStack` but it additionally (**Is it not**?)

 a. takes string parameter that serves as stdin for running application.

 b. works in both sync/async mode.

 c. it works out of section - for .onInit check outs.

8. `ExecCmd`: Same as `ExecDos` but it doesn&#39;t require these


        ExpandEnvStrings $3 %COMSPEC% 
        ExecDos::exec  /C 


 parts. **Am I correct?**

Exec vs ExecWait vs ExecShell vs nsExec::Exec vs nsExec::ExecToLog vs nsExec::ExecToStack vs ExecDos vs ExeCmd

I have a **batch file** that does a bunch of things and at the end needs to **open up a web browser** to a page. Is there a way to, in essence, call `ShellExecute` on a **http** to open the web page?

Windows Command Prompt



Content Type	Original Author	Original Content on Stackoverflow
Question	trilawney	View Question on Stackoverflow
Solution 1 - Shell	merryprankster	View Answer on Stackoverflow

How to Pass parameters for a Ant script , which is invoked via shell script?

Shell Problem Overview

Shell Solutions

Solution 1 - Shell

How do files get into the External Dependencies in Visual Studio C++?

if (cin >> x) - Why can you use that condition?

Attributions