Commonly used adb logcat options

 

adb version tested

$ adb --version
Android Debug Bridge version 1.0.41
Version 31.0.2-7242960

Print all options

$ adb logcat -h              
Usage: logcat [options] [filterspecs]

General options:
  -b, --buffer=<buffer>       Request alternate ring buffer(s):
                                main system radio events crash default all
                              Additionally, 'kernel' for userdebug and eng builds, and
......

Check logcat buffer size

  -g, --buffer-size           Get the size of the ring buffers within logd.



$ adb logcat -g
main: ring buffer is 5 MiB (4 MiB consumed), max entry is 5120 B, max payload is 4068 B
system: ring buffer is 2 MiB (1 MiB consumed), max entry is 5120 B, max payload is 4068 B
crash: ring buffer is 256 KiB (0 B consumed), max entry is 5120 B, max payload is 4068 B
kernel: ring buffer is 256 KiB (0 B consumed), max entry is 5120 B, max payload is 4068 B

Change logcat buffer size

  -b, --buffer=<buffer>       Request alternate ring buffer(s):
                                main system radio events crash default all
                              Additionally, 'kernel' for userdebug and eng builds, and
                              'security' for Device Owner installations.
                              Multiple -b parameters or comma separated list of buffers are
                              allowed. Buffers are interleaved.
                              Default -b main,system,crash,kernel.

  -G, --buffer-size=<size>    Set size of a ring buffer in logd. May suffix with K or M.
                              This can individually control each buffer's size with -b.



set system buffer

$ adb logcat -G 5M -b system

$ adb logcat -g             
main: ring buffer is 5 MiB (4 MiB consumed), max entry is 5120 B, max payload is 4068 B
system: ring buffer is 5 MiB (1 MiB consumed), max entry is 5120 B, max payload is 4068 B
crash: ring buffer is 256 KiB (0 B consumed), max entry is 5120 B, max payload is 4068 B
kernel: ring buffer is 256 KiB (0 B consumed), max entry is 5120 B, max payload is 4068 B

set all buffer

$ adb logcat -G 5M          

$ adb logcat -g   
main: ring buffer is 5 MiB (4 MiB consumed), max entry is 5120 B, max payload is 4068 B
system: ring buffer is 5 MiB (1 MiB consumed), max entry is 5120 B, max payload is 4068 B
crash: ring buffer is 5 MiB (0 B consumed), max entry is 5120 B, max payload is 4068 B
kernel: ring buffer is 5 MiB (0 B consumed), max entry is 5120 B, max payload is 4068 B

Clear all logs

  -c, --clear                 Clear (flush) the entire log and exit.
                              if -f is specified, clear the specified file and its related rotated
                              log files instead.
                              if -L is specified, clear pstore log instead.



$ adb logcat -c

Dump logs(non block)

  -d                          Dump the log and then exit (don't block).



$ adb logcat -d
--------- beginning of system
12-30 15:11:05.979  1132  5037 I ActivityManager: Process com.samsung.android.dqagent
--------- beginning of main
12-30 15:11:05.980   825   825 I Zygote  : Process 25662 exited due to signal 9 (Killed)
12-30 15:11:05.980   604   604 I lmkd    : cached 5, sandbox(not0) 2
12-30 15:11:05.981  1132  1423 I libprocessgroup: Successfully killed process cgroup 
......
12-30 15:11:14.978   805   805 E audit   : type=1327 audit(1640844674.973:574366029):
12-30 15:11:14.978   805   805 E audit   : type=1400 audit(1640844674.977:574366030):
12-30 15:11:14.978   805   805 E audit   : type=1300 audit(1640844674.977:574366030):
$

Save logs(block)

Option (adb logcat -h)
Outfile files:
  -f, --file=<file>           Log to file instead of stdout.
  -r, --rotate-kbytes=<n>     Rotate log every <n> kbytes. Requires -f option.
  -n, --rotate-count=<count>  Sets max number of rotated logs to <count>, default 4.



1000K, Max 20, save to /storage/emulated/0/logcat

$ adb logcat -r 1000 -n 20 -f /storage/emulated/0/logcat/logcat.log

$ adb shell ls -lh /storage/emulated/0/logcat/
total 676K
-rw-rw---- 1 root everybody 634K 2021-12-30 15:24 logcat.log
-rw-rw---- 1 root everybody 0.9M 2021-12-30 15:24 logcat.log.01

$ adb shell ls -lh /storage/emulated/0/logcat/
total 1.0M
-rw-rw---- 1 root everybody 222K 2021-12-30 15:25 logcat.log
-rw-rw---- 1 root everybody 0.9M 2021-12-30 15:24 logcat.log.01
-rw-rw---- 1 root everybody 0.9M 2021-12-30 15:24 logcat.log.02

Filtering

Filtering:
  -s                          Set default filter to silent. Equivalent to filterspec '*:S'
......

filterspecs are a series of 
  <tag>[:priority]

where <tag> is a log component tag (or * for all) and priority is:
  V    Verbose (default for <tag>)
  D    Debug (default for '*')
  I    Info
  W    Warn
  E    Error
  F    Fatal
  S    Silent (suppress all output)



$ adb logcat -s "AlarmManager:*" "BatteryStatsService:*"
12-30 15:39:24.326  1132  1836 E AlarmManager: Set nextNonWakeup as mNextNonWakeupDelive
12-30 15:39:24.353  1132  4035 I BatteryStatsService: In wakeup_callback: resumed from 
12-30 15:39:25.054  1132  4935 I BatteryStatsService: In wakeup_callback: suspend aborted
12-30 15:39:26.410  1132  3545 V AlarmManager: unblockMARsRestrictedAlarmsForUidPackage

Print with thread, time

-v <format>, --format=<format> options:
  Sets log print format verb and adverbs, where <format> is:
    brief long process raw tag thread threadtime time


default : Depends on the adb version
$ adb logcat -s "AlarmManager:*"
12-30 15:26:40.860  1132  1836 E AlarmManager: Set nextNonWakeup as mNextNonWakeupDelive

$ adb logcat -s "AlarmManager:*" -v time
12-30 15:22:01.749 E/AlarmManager( 1132): Set nextNonWakeup as mNextNonWakeupDeliveryTime

$ adb logcat -s "AlarmManager:*" -v thread
E( 1132: 1836) Set nextNonWakeup as mNextNonWakeupDeliveryTime=781912438 , orig nextNonWakeup=0

$ adb logcat -s "AlarmManager:*" -v threadtime
12-30 15:14:24.021  1132  1836 E AlarmManager: Set nextNonWakeup as mNextNonWakeupDelive

Apply color by log level

$ adb logcat -v color

Show/hide JScrollPane scrollbar

 Set using setHorizontalScrollBarPolicy, setVerticalScrollBarPolicy

package test.swing;

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.*;

// JScrollPane scrollbar show / hide
public class MainTest {
    public static void main(String[] args) {
        MainUI mainUI = new MainUI();
        mainUI.setVisible(true);
    }
}

class MainUI extends JFrame {
    JScrollPane scrollPane1 = null;
    JScrollPane scrollPane2 = null;
    JScrollPane scrollPane3 = null;
    JTable table1 = null;
    JTable table2 = null;
    JTable table3 = null;
    DefaultTableModel tableModel = null;

    MainUI() {
        setPreferredSize(new Dimension(400, 600));
        setLayout(new GridLayout(3, 1));

        System.out.println("JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED = " + JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        System.out.println("JScrollPane.HORIZONTAL_SCROLLBAR_NEVER = " + JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        System.out.println("JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS = " + JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

        System.out.println("JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED = " + JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
        System.out.println("JScrollPane.VERTICAL_SCROLLBAR_NEVER = " + JScrollPane.VERTICAL_SCROLLBAR_NEVER);
        System.out.println("JScrollPane.VERTICAL_SCROLLBAR_ALWAYS = " + JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

        table1 = new JTable();
        tableModel = (DefaultTableModel) table1.getModel();
        tableModel.addColumn("Column");
        tableModel.addRow(new Object[]{"SCROLLBAR_AS_NEEDED"});
        scrollPane1 = new JScrollPane(table1);
        add(scrollPane1);

        System.out.println("default h policy = " + scrollPane1.getHorizontalScrollBarPolicy() + ", v policy = " + scrollPane1.getVerticalScrollBarPolicy());

        table2 = new JTable();
        tableModel = (DefaultTableModel) table2.getModel();
        tableModel.addColumn("Column");
        tableModel.addRow(new Object[]{"HORIZONTAL_SCROLLBAR_NEVER"});
        tableModel.addRow(new Object[]{"VERTICAL_SCROLLBAR_ALWAYS"});
        scrollPane2 = new JScrollPane(table2);
        scrollPane2.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        scrollPane2.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        add(scrollPane2);

        table3 = new JTable();
        tableModel = (DefaultTableModel) table3.getModel();
        tableModel.addColumn("Column");
        tableModel.addRow(new Object[]{"HORIZONTAL_SCROLLBAR_ALWAYS"});
        tableModel.addRow(new Object[]{"VERTICAL_SCROLLBAR_NEVER"});
        scrollPane3 = new JScrollPane(table3);
        scrollPane3.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        scrollPane3.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
        add(scrollPane3);

        pack();
    }
}

Run

JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED = 30
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER = 31
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS = 32
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED = 20
JScrollPane.VERTICAL_SCROLLBAR_NEVER = 21
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS = 22
default h policy = 30, v policy = 20

Resize panel when component moves to the next line in FlowLayout

 Code to adjust the height of the JPanel to the last component when the Resize event occurs

package test.swing;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

// resize panel
public class MainTest {
    public static void main(String[] args) {
        MainUI mainUI = new MainUI();
        mainUI.setVisible(true);
    }
}

class MainUI extends JFrame {
    FlowLayout flowLayout = new FlowLayout(FlowLayout.LEFT, 0, 0);
    JPanel resizePane = new JPanel(flowLayout);
    JButton testBtn1 = new JButton("TEST 1");
    JButton testBtn2 = new JButton("TEST 2");
    JButton testBtn3 = new JButton("TEST 3");
    JButton testBtn4 = new JButton("TEST 4");
    JButton testBtn5 = new JButton("TEST 5");
    JComponent lastComponent = testBtn5;

    MainUI() {
        setPreferredSize(new Dimension(500, 300));
        setLayout(new BorderLayout());

        resizePane.setBackground(Color.BLUE);
        resizePane.addComponentListener(new ComponentAdapter() {
            Point prevPoint = null;

            @Override
            public void componentResized(ComponentEvent e) {
                super.componentResized(e);
                if (prevPoint == null || prevPoint.y != lastComponent.getLocation().y) {
                    System.out.println("lastComonent moved to " + lastComponent.getLocation());
                    resizePane.setPreferredSize(new Dimension(resizePane.getPreferredSize().width, lastComponent.getLocation().y + lastComponent.getHeight()));
                    resizePane.updateUI();
                }
                prevPoint = lastComponent.getLocation();
            }
        });

        resizePane.add(testBtn1);
        resizePane.add(testBtn2);
        resizePane.add(testBtn3);
        resizePane.add(testBtn4);
        resizePane.add(testBtn5);
        add(resizePane, BorderLayout.NORTH);

        JPanel pane = new JPanel();
        pane.add(new JLabel("TEST TEST"));
        add(pane, BorderLayout.CENTER);

        pack();
    }
}

RUN

Install MS teams on Ubuntu

https://docs.microsoft.com/microsoftteams/get-clients#install-manually-from-the-command-line 

How to install

# For entering passwd when sudo is first executed
$ sudo ls 

$ curl https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -

$ sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/ms-teams stable main" > /etc/apt/sources.list.d/teams.list'

$ sudo apt update
$ sudo apt install teams

Show tooltip when JComboBox key is pressed

 Code that shows tooltip when key occurs by key listener in JComboBox

package test.swing;

import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;

// key event tooltip
public class MainTest {
    public static void main(String[] args) {
        MainUI mainUI = new MainUI();
        mainUI.setVisible(true);
    }
}

class TestComboBox extends JComboBox {
    JTextField mTf = null;
    public TestComboBox() {
        super();
        mTf = (JTextField) editor.getEditorComponent();
        mTf.setToolTipText("TextField : ");
        mTf.addKeyListener(new KeyHandler());
    }

    class KeyHandler extends KeyAdapter {
        @Override
        public void keyReleased(KeyEvent e) {
            // set tooltip
            mTf.setToolTipText("TextField : " + mTf.getText());
            // show tooltip
            ToolTipManager.sharedInstance().mouseMoved(new MouseEvent(mTf, 0, 0, 0,0, 0, 0, false));
            super.keyReleased(e);
        }
    }
}

class MainUI extends JFrame {
    MainUI() {
        setPreferredSize(new Dimension(400, 300));
        setLayout(new FlowLayout());
        TestComboBox combo = new TestComboBox();
        combo.setToolTipText("ComboBox");
        combo.setEditable(true);
        add(combo);
        pack();
    }
}

Converting java code to kotlin code (intellij)

Converting java code to kotlin code when pasting

https://www.jetbrains.com/help/idea/2021.2/settings-smart-keys.html

When pasting in intellij, when the convert popup appears, click yes

converted code

How to enable convert kotlin in setting

java swing dynamic tooltip, multi-line tooltip

Implemented with getToolTipText method override

https://docs.oracle.com/javase/8/docs/api/javax/swing/JComponent.html#getToolTipText-java.awt.event.MouseEvent-

package test.swing;

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseEvent;

// dynamic tooltip
public class MainTest {
    public static void main(String[] args) {
        MainUI mainUI = new MainUI();
        mainUI.setVisible(true);
    }
}

class ToolTipButton extends JButton {
    boolean mIsNum = true;

    public ToolTipButton(String text) {
        super(text);
    }

    // 1. use setToolTipText
    @Override
    public String getToolTipText(MouseEvent event) {
        if (mIsNum) {
            setToolTipText("0123456789");
        }
        else {
            setToolTipText("ABCDEFG");
        }
        mIsNum = !mIsNum;
        return super.getToolTipText(event);
    }

    // 2. return text directly
    @Override
    public String getToolTipText(MouseEvent event) {
        String text = "";
        if (mIsNum) {
            text = "0123456789";
        }
        else {
            text = "ABCDEFG";
        }
        mIsNum = !mIsNum;
        return text;
    }
}

class MainUI extends JFrame {

    MainUI() {
        setPreferredSize(new Dimension(400, 300));
        setLayout(new FlowLayout());
        JButton button = new ToolTipButton("TEST");
        button.setToolTipText("");
        button.setPreferredSize(new Dimension(100, 100));
        add(button);
        pack();
    }
}

Multi-line tooltip

setToolTipText("<html>a<br>b</html>");

Remove gap in FlowLayout in swing

https://docs.oracle.com/en/java/javase/17/docs/api/java.desktop/java/awt/FlowLayout.html

// When creating layout
public FlowLayout(int align, int hgap, int vgap)
new FlowLayout(FlowLayout.LEADING, 0, 0);

// remove horizontal gap
public void setHgap(int hgap)
layout.setHgap(0);

// remove vertical gap
public void setVgap(int vgap)
layout.setVgap(0);

Registering a Java Swing KeyStroke

Close window when ESC is pressed

package test.swing;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.WindowEvent;

public class MainTest {
    public static void main(String[] args) {
        MainUI mainUI = new MainUI();
        mainUI.setVisible(true);
    }
}

class MainUI extends JFrame {
    MainUI() {
        setPreferredSize(new Dimension(400, 300));
        setLayout(new FlowLayout());
        JButton button = new JButton("TEST");
        button.setPreferredSize(new Dimension(100, 100));
        add(button);
        pack();

        KeyStroke escStroke = KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0);
        String actionMapKey = getClass().getName() + ":WINDOW_CLOSING";
        Action closingAction = new AbstractAction() {
            public void actionPerformed(ActionEvent event) {
                MainUI.this.dispatchEvent(new WindowEvent(MainUI.this, WindowEvent.WINDOW_CLOSING));
            }
        };

        installKeyStroke(this, escStroke, actionMapKey, closingAction);
    }

    public void installKeyStroke(final RootPaneContainer container, final KeyStroke stroke, final String actionMapKey, final Action action) {
        JRootPane rootPane = container.getRootPane();
        rootPane.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(stroke, actionMapKey);
        rootPane.getActionMap().put(actionMapKey, action);
    }
}

Generate a key with the class name to be registered (to prevent duplication)

String actionMapKey = getClass().getName() + ":WINDOW_CLOSING";

 

Deadlocks that occur frequently

 Single thread deadlock

#include <mutex>

std::mutex mutex1;    
    
/////////// Lock is called again in the locked state    
void deadlock_1() {    
    std::lock_guard<std::mutex> lockGuard(mutex1);    
    deadlock_1_1();    
}

     
void deadlock_1_1() {    
    std::lock_guard<std::mutex> lockGuard(mutex1); // Attempt to lock again on a locked lock   
}    
     
////////// When the lock is applied, it spins around and calls the lock again, if it spins a lot and the lock is caught...    
void deadlock_2() {    
    std::lock_guard<std::mutex> lockGuard(mutex1);    
    deadlock_2_1();    
}    

void deadlock_2_1() {
    deadlock_2();                               // Try lock again with recursive call
    
}

Multi Thread Deadlock - Deadlock occurs when executed in numerical order

#include <mutex>


std::mutex mutex1;    
std::mutex mutex2; 

void deadlock_3_thread_1() {
    std::lock_guard<std::mutex> lockGuard(mutex1);    // 1   
    std::lock_guard<std::mutex> lockGuard(mutex2);    // 3
}                         
                          
void deadlock_3_thread_2() {
    std::lock_guard<std::mutex> lockGuard(mutex2);    // 2
    std::lock_guard<std::mutex> lockGuard(mutex1);    // 3
}

install ubuntu c++ manpage

 Used to simply check the contents of c++ std api in the terminal

No manpage

$ man std::lock_guard                        
No manual entry for std::lock_guard

Install manpage

$ sudo apt install libstdc++-10-doc

Show manpage

$ man std::lock_guard | cat
std::lock_guard< _Mutex >(3cxx)                                                                                                                                                                                                       std::lock_guard< _Mutex >(3cxx)

NAME
       std::lock_guard< _Mutex > - A simple scoped lock type.
......

Install c++ manpages on ubuntu

 When you simply check the contents of c++ std api in terminal

$ man std::lock_guard                        
No manual entry for std::lock_guard

$ sudo apt install libstdc++-10-doc

$ man std::lock_guard | cat
std::lock_guard< _Mutex >(3cxx)                                                                                                                                                                                                       std::lock_guard< _Mutex >(3cxx)

NAME
       std::lock_guard< _Mutex > - A simple scoped lock type.
......

Using 7zip on ubuntu

$ sudo apt-get install p7zip-full

$ 7z

7-Zip [64] 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18
p7zip Version 9.20 (locale=C,Utf16=off,HugeFiles=on,8 CPUs)

Usage: 7z <command> [<switches>...] <archive_name> [<file_names>...]
       [<@listfiles...>]

Print logcat with adb command

 How to add logcat log via "log" command

$ log --help
usage: log [-p PRI] [-t TAG] MESSAGE...

Logs message to logcat.

-p	Use the given priority instead of INFO:
	d: DEBUG  e: ERROR  f: FATAL  i: INFO  v: VERBOSE  w: WARN  s: SILENT
-t	Use the given tag instead of "log"

++ operation in shell script

Test script

#! sh

num=0

echo $num
num=$(($num + 1))
echo $num
num=$((num + 1))
echo $num
let num++
echo $num

Execution result

❯ ./test.sh          
0
1
2
3

linux existing command replacement command i use

Check file and directory capacity

du - ncdu (can be checked while moving the directory)
dev.yorhel.nl/ncdu/scr

ls - lsd (many colors and icons according to files and directories)
github.com/Peltoche/lsd

find - fd-find (more intuitive command option, color)
github.com/sharkdp/fd

cd - enhancd (select from the list of previously moved paths when entering an incorrect path)
github.com/b4b4r07/enhancd

grep - ripgrep (result split by file)
github.com/BurntSushi/ripgrep