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Please explain the exec() function and its family
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int execl(const char *path, const char *arg, ...);
int execlp(const char *file, const char *arg, ...);
int execle(const char *path, const char *arg, ..., char * const envp[]);
int execv(const char *path, char *const argv[]);
int execvp(const char *file, char *const argv[]);
int execvpe(const char *...
Run a single migration file
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You can just run the code directly out of the ruby file:
rails console
>> require "db/migrate/20090408054532_add_foos.rb"
>> AddFoos.up
Note: newer versions of rails may require AddFoos.new.up rather than AddFoos.up.
An alternative way (without IRB) which reli...
How do I save a UIImage to a file?
...e you can create subfolders in the documents folder of your app. You use NSFileManager to do that.
You use UIImagePNGRepresentation to convert your image to NSData and save that to disk.
// Create path.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES...
In plain English, what does “git reset” do?
...t --mixed. It resets the index, but not the work tree. This means all your files are intact, but any differences between the original commit and the one you reset to will show up as local modifications (or untracked files) with git status. Use this when you realize you made some bad commits, but you...
Jar Mismatch Found 2 versions of android-support-v4.jar in the dependency list
...ons of an Android app (free/paid). I have an Android Library that contains files common to both. I created a new Android project and am trying to use the Library but get the error below:
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What is Android keystore file, and what is it used for?
...t particularly I am interested in it's use for Android. What is a keystore file, and what is it used for?
4 Answers
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Set the value of a variable with the result of a command in a Windows batch file
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To do what Jesse describes, from a Windows batch file you will need to write:
for /f "delims=" %%a in ('ver') do @set foobar=%%a
But, I instead suggest using Cygwin on your Windows system if you are used to Unix-type scripting.
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What is the best way to create constants in Objective-C
I am creating a Reddit client for learning purposes. I need to have a file with constants in it. I was thinking about importing the file in the Reddit-Prefix.pch file to make the constants available to all the files. Is it a good way of doing things? Also, I've done my research and found several...
Setting property 'source' to 'org.eclipse.jst.jee.server:JSFTut' did not find a matching property
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I've noticed that if you have the server.xml file open it does not add the context back in. I just stopped the server and closed the server.xml file then re-added the project. THought I would mentioned it in case anyone else runs into the same problem.
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How do you see the entire command history in interactive Python?
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If you want to write the history to a file:
import readline
readline.write_history_file('python_history.txt')
The help function gives:
Help on built-in function write_history_file in module readline:
write_history_file(...)
write_history_file([filename])...