[Linux] Check os version in Linux

> cat /etc/os-release

root@58d01b6b8b17:/# cat /etc/os-release
NAME="Ubuntu"
VERSION="20.04.2 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.2 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

[Linux] Replace one substring for another string in shell script

first="I love me and Mary"
second="conan"
first=${first/me/$second}

[Linux] How to get and set SW/HW date in linux

get date
- Software
> date


- Hardware
hwclock


set date
- Software
> date


- Hardware
hwclock

[C#, Unity] Unity Text text super box with ‘...’ ellipsis at the end

public void SetTextWithEllipsis(Text textComponent, string value)
        {
            var generator = new TextGenerator();
            var rectTransform = textComponent.GetComponent<RectTransform>();
            var settings = textComponent.GetGenerationSettings(rectTransform.rect.size);
            generator.Populate(value, settings);
            var characterCountVisible = generator.characterCountVisible;
            var updatedText = value;
            if (value.Length > characterCountVisible)
            {
                updatedText = value.Substring(0, characterCountVisible - 3);
                updatedText += "…";
            }
            textComponent.text = updatedText;
        }


Example:

Transform tt = gameObject.transform.Find("Text");
SetTextWithEllipsis(tt.gameObject.GetComponent<Text>(), "fffffffffffffffffffffffff");

中英文 符號 對照

’	Apostrophe	撇號
（）	Bracket (英式) / Parentheses (美式)	括號
：	Colon	冒號
，	Comma	逗號
－	Dash	破折號
…	Ellipsis	省略號
！	Exclamation Mark (英式) / Point (美式)	感嘆號
.	Full Stop (英式) / Period (美式)	句號
《　》	Guillemet	書名號
–	Hyphen	連字號
？	Question Mark	問號
＂＂	Quotation Mark	引號
；	Semicolon	分號
/	Slash	斜線

[C#, unity] Fixed: The name instantiate' does not exist in the current context

                        Transform cloneTransform = m_fields.GetChild(nColumn).GetChild(nIndex);
                        Transform tempTransform = Instantiate(cloneTransform).transform;
                        tempTransform.SetParent(m_fields.GetChild(nColumn));
                        tempTransform.localPosition = Vector3.zero;
                        tempTransform.localRotation = Quaternion.identity;
                        tempTransform.localScale = Vector3.one;


Answer:

Transform tempTransform = GameObject.Instantiate(cloneTransform).transform;

[C#, Unity] String to Color; Color to String

String to Color
string col = "#FF8400";
this.BackColor = System.Drawing.ColorTranslator.FromHtml(col);


Color to String Color
mycolor = this.BackColor;
string strcol = System.Drawing.ColorTranslator.ToHtml(mycolor);
MessageBox.Show(strcol);

Unity:
public void SetImageColor(string strColor)
{
    Color clr;
    if (ColorUtility.TryParseHtmlString(strColor, out clr))
        this.gameObject.GetComponent<Image>().color = clr;
}

[C#] How to get the name of current function?

System.Reflection.MethodBase.GetCurrentMethod().Name

[Linux] How to add a literal tab character in a bash shell?

$'\t'

ex: $ sort -t $'\t'
$ echo -n $'\t'

$ echo -e ' \t ' | hexdump -C
00000000 20 09 20 0a | . .| 00000004

[Linux] How to find all files containing specific text on Linux?

grep -rnw '/path/to/somewhere/' -e 'pattern'

• -r or -R is recursive,
• -n is line number, and
• -w stands for match the whole word.
• -l (lower-case L) can be added to just give the file name of matching files.

P.S. example: to find "if ["

grep -rnw '/path/to/somewhere/' -e 'if \['




[Linux] Create encrypted (password protected) zip/upzip file

 - zip 

This will prompt for a password:

zip --encrypt file.zip files

This is more insecure, as the password is entered/shown as plain text:

zip --password (password) file.zip files

Warning, the standard zip encryption is very weak and is easily cracked.

- unzip 

unzip -P (password) file.zip

[Linux] How can I get what my main function has returned

Most shells store the exit code of the previous run command in $? so you can store or display it.

$ ./a.out
$ echo $?     # note - after this command $? contains the exit code of echo!

or

$ ./a.out
$ exit_code=$?    # save the exit code in another shell variable.

[Linux] Checking if a directory exists in Unix (system call)

#include <sys/stat.h>

struct stat sb;

if (stat(pathname, &sb) == 0 && S_ISDIR(sb.st_mode))
{
    ...it is a directory...
}

[Xcode] Fixed: Build error that it import Objective-C codes in the .cpp?

Build error: (NSObjCRuntime.h & NSObject)

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSObjCRuntime.h:371:1: Expected unqualified-id

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSObjCRuntime.h:373:19: Unknown type name 'NSString'
...

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/objc/NSObject.h:11:1: Expected unqualified-id
...


[Solution]
rename extension name from .cpp into .mm

[Xcode] Fixed: _CMAudioFormatDescriptionGetStreamBasicDescription", referenced from: -[captureNSObject init] in captureNSObject.o

I have a project to build some code,  and then it has error in the follow:

Undefined symbols for architecture x86_64:

  "_CMAudioFormatDescriptionGetStreamBasicDescription", referenced from:

      -[captureNSObject init] in captureNSObject.o

  "_CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer", referenced from:

      -[captureNSObject captureOutput:didOutputSampleBuffer:fromConnection:] in captureNSObject.o

  "_CMSampleBufferGetNumSamples", referenced from:

      -[captureNSObject captureOutput:didOutputSampleBuffer:fromConnection:] in captureNSObject.o

ld: symbol(s) not found for architecture x86_64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

[Solution]

Add CoreMedia.framework into "Linked Frameworks and Libraries".

[Xcode] Enable/disable a button

@property (retain, nonatomic) IBOutlet UIButton *btnButton;

enable/disable like this in .m file:

btnButton.enabled = NO; // disable button
btnButton.enabled = YES; // enable button

[Xcode] How to convert int to NSString

    int nNum = 100;

    NSString* str = [[NSString alloc]initWithFormat:@"%d", nNum];

[Xcode] How to quit the application when the window closes

If you want an application to quit (terminate) when the window is closed, you can do this:

-(BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication*)theApplication
{
    return YES;
}

[Xcode] How to convert between NSTextField and NSString

// NSString --> NSTextField

NSTextField * txtField = [[NSTextField alloc] init];

NSString *str = @“1234”;

txtField.stringValue = str;

// NSTextField --> NSString

NSString *str1 = txtField.stringValue;

[Xcode] How to convert byte array to NSString

Byte* btData = new Byte[12];

memset(btData, 0, sizeof(Byte) * 12);

...

NSData *data = [NSData dataWithBytes:btData length:sizeof(btData)];

NSString *string = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];