larshaendler

Lee Benfield's Java decompiler CFR is straight forward and can even batch decompile jar container. 

1. Download the most recent version of CFR (crf 0.1.15 at the time of writing)

wget http://www.benf.org/other/cfr/cfr_0_115.jar

2. Run decompile with output into terminal

java -jar cfr_0_115.jar javaclasstodecompiles.class

larshaendler

avconv is part of the libav tools. Just install those:

sudo apt install libav-tools

larshaendler

Sometimes you have a data file that needs sorting not just from left to right but by multiple values in the middle of each line. That is when you make use of the -k option / flag. 

Let's look at the following data file; let's call it test.txt. It starts with a timestamp in the German date format; meaning dd.mm.yyyy.

19.09.1942 12:34              Nekros
05.03.1945 20:15              Inaros
01.01.1969 23:55              Banshee
02.01.1969 20:15              Mesa
03.01.1969 12:00              Nezha
19.02.1969 17:38 Nova

larshaendler

find all files older than 30 days recursively in current directory

find ./ -type f -mtime +30

Variation 1 - find all files older than 30 days that end with .log

find ./ -name "*.log" -type f -mtime +30

Variation 2 - delete all files older than 30 days that end with .log

larshaendler

PHP example:

$location = 'tree';
$format = 'There are 5 monkeys in the %s';
echo sprintf($format, $location);
#output: There are 5 monkeys in the tree

Java String.format

larshaendler

//inputPath format "/usr/bin/java/"
public static String getParentDirectoryPath(String inputPath)
{
	String resultString = "";
	String regEx = "(.*\\/)\\S+\\/$";
	Pattern regexPattern = Pattern.compile(regEx);
	Matcher match = regexPattern.matcher(inputPath);
	 
	if(match.find()) {
		resultString = match.group(1);

larshaendler

iconv -f ISO-8859-1 -t UTF-8 in.txt > out.txt

-f ENCODING the encoding of the input -t ENCODING the encoding of the output

larshaendler

Create a MySQL / MariaDB dump on command line

mysqldump -u [uname] -p db_name > db_backup.sql

Import a dump into MySQL / MariaDB

mysql -u username -p db_name < db_backup.sql

Additional info

larshaendler

Extracting a certain pattern (e.g. date) with regex grouping from a string (e.g. file name).

String resultString = "";
String fileName = "012345467_20120502T230108_file-name.zip";
String regex = "_(\\d{8})T.*?"; //regex for date

Pattern regexPattern = Pattern.compile(regex);
Matcher match = regexPattern.matcher(fileName);

if(match.find())

larshaendler

There are two ways to install Atom using a repository. The first is by added the repo to apt and the second is just using snap for installation.

Install Atom using apt

sudo add-apt-repository ppa:webupd8team/atom
sudo apt update
sudo apt install atom

Install Atom using snap If you have not installed snap yet: