- <project>
- [...]
- <build>
- <plugins>
- <plugin>
- <groupId>org.apache.maven.plugins</groupId>
- <artifactId>maven-surefire-plugin</artifactId>
- <version>3.0.0</version>
- <configuration>
- <skipTests>true</skipTests>
- </configuration>
- </plugin>
- </plugins>
- </build>
- [...]
- </project>
You can also skip the tests via the command line by executing the following command:
- mvn install -DskipTests
If you absolutely must, you can also use the maven.test.skip property to skip compiling the tests. maven.test.skip is honored by Surefire, Failsafe and the Compiler Plugin.
- mvn install -Dmaven.test.skip=true
Bash is a sort of Shell, other shells, fx: Fish, Zsh, Ksh
A Terminal, also called a shell, is a GUI to interact with the kernel.
/(forward slash): Root
/home/username: each user has a personal folder
/bin: command binaries.
/etc: local system configuration files
/lib: shared libs shared for system boot
/opt: the third-party tools
/var: variable files, fx: log files
ls -a: list all files including hidden ones.
ls -l: list files in a long format.
ls -l *.txt
cd: change the current directory
.. indicates the parent folder
mkdir: make a new folder
mkdir folder1 folder2: creating several folders
mkdir -p folder/nested-folder: creating m-nested folders
rmdir: remove a folder
rm: remove one file or multiple files
rm blue red yellow
rm -v blue red yellow
-v: verbose. -r: recursive -i: interactive -f: force
rm -rf folder-name
touch: if the file is not existed, create one, else update to a new timestamp.
touch new-file-name
open: open a file or directory just like double-clicked file icon.
open. open the current folder in a graphic presentation
open file-name: open the file in OS default text editor
> : redirect output console
date > newFile.text: output current date to designated file, and overwrite the file entirely.
>>: redirect out the console and appending
date>> newFile.text: out current date to designated file, and appending.
cp: copy file or folder
less: a UI showing the entire file, scrolling down and up.
less file-name
WC: word count
wc -l file-name: shows line number in a file
wc -w file-name: shows how many words are in a file
piping |: taking one command output as input of another command.
Env var
expending dollar sign or tilde
dollar sign path
echo * all path names
echo *.txt
? matching each single character
cry0l1t3@htb[/htb]$ ls -l /etc/passwd
- rwx rw- r-- 1 root root 1641 May 4 23:42 /etc/passwd
- --- --- --- | | | | |__________|
| | | | | | | | |_ Date
| | | | | | | |__________ File Size
| | | | | | |_______________ Group
| | | | | |____________________ User
| | | | |_______________________ Number of hard links
| | | |_ Permission of others (read)
| | |_____ Permissions of the group (read, write)
| |_________ Permissions of the owner (read, write, execute)
|____________ File type (- = File, d = Directory, l = Link, ... )chmod 777 file-name : change file read-write-executable
find . -name fileName: find the current folder by name
which: shows the path to a file
which file-name: locate a file
ps: shows all processes
ps -ef: extended format
ps -ef | grep bash
kill PID: kill by its process ID
top: show statistics of system usage
wget URI: download resources
su: switch user to log in as someone else
exit: log out a user account
sudo: super user do, run a command as a root user
sudo apt update: update the APT package index in line with the repository.
sudo apt upgrade: update the installed packages to the latest version.
sudo apt upgrade specific-package: update an installed package to the newest version.
sudo apt install package-name: install package
source file-name [argument]: shell built-in command that can execute a file containing a list of shell commands.
export: built-in shell command to mark env variable to export the child processes(change visibilities).
sh xxx.sh: execute a script file
Explicit locks, such as those provided by the java.util.concurrent.locks package (e.g., ReentrantLock, ReadWriteLock), offer several advantages over using intrinsic locks provided by synchronized blocks or methods. Some of the key benefits of using explicit locks are:
Flexibility: Explicit locks offer more flexibility in terms of lock acquisition and release. You can lock and unlock the lock object at different scopes and in separate blocks of code, which is not possible with synchronized blocks or methods.
Fairness: ReentrantLock allows you to specify fairness when creating the lock object. When a lock is fair, it grants access to the longest-waiting thread. Intrinsic locks provided by synchronized blocks or methods do not have a fairness option and may lead to thread starvation in some scenarios.
javaLock lock = new ReentrantLock(true); // Create a fair lock
tryLock() method, which allows a thread to attempt to acquire the lock without waiting indefinitely. This can help avoid deadlocks and improve performance in some cases.javaif (lock.tryLock()) {
try {
// Perform the operation
} finally {
lock.unlock();
}
} else {
// Handle the lock not being acquired
}
lockInterruptibly() method, which allows a thread to be interrupted while waiting to acquire the lock. Intrinsic locks do not support this functionality.javatry {
lock.lockInterruptibly();
try {
// Perform the operation
} finally {
lock.unlock();
}
} catch (InterruptedException e) {
// Handle the interruption
}
ReadWriteLock interface provides separate locks for read and write operations, allowing multiple threads to read shared data simultaneously while still providing exclusive access for write operations. This can lead to better performance in scenarios with more reads than writes.javaReadWriteLock rwLock = new ReentrantReadWriteLock();
Lock readLock = rwLock.readLock();
Lock writeLock = rwLock.writeLock();
While explicit locks offer several advantages, they also require more careful handling and can be more error-prone due to the need for manual lock management. When choosing between explicit locks and intrinsic locks, consider the specific use case, the complexity of the code, and the required functionality.
For example, a URL that includes a query string parameter for a search term might look like this:
https://www.example.com/search?term=best+restaurants