Exercício - Utilizar a ajuda

  • 1 minuto

Depois de encontrar um cmdlet que deseja usar, você pode saber mais sobre ele. Por exemplo, você pode aprender sobre as diferentes maneiras de chamá-lo, quais parâmetros você pode usar e exemplos de casos de uso.

Use Get-Help para descobrir comandos

Use o Get-Help cmdlet para saber mais sobre cmdlets.

  1. Execute o comando Get-Help:

    Get-Help -Name Get-FileHash

    Este comando produz uma saída semelhante ao seguinte texto:

    NAME
    Get-FileHash

SYNOPSIS
    Computes the hash value for a file by using a specified hash algorithm.

SYNTAX
    Get-FileHash [-InputStream] <System.IO.Stream> [[-Algorithm] {SHA1 | SHA256 | SHA384 | SHA512 | MD5}] 
    [<CommonParameters>]

    Get-FileHash [-LiteralPath] <System.String[]> [[-Algorithm] {SHA1 | SHA256 | SHA384 | SHA512 | MD5}] 
    [<CommonParameters>]

    Get-FileHash [-Path] <System.String[]> [[-Algorithm] {SHA1 | SHA256 | SHA384 | SHA512 | MD5}] 
    [<CommonParameters>]

DESCRIPTION
    The `Get-FileHash` cmdlet computes the hash value for a file by using a specified hash algorithm. A hash value 
    is a unique value that corresponds to the content of the file. Rather than identifying the contents of a file 
    by its file name, extension, or other designation, a hash assigns a unique value to the contents of a file. 
    File names and extensions can be changed without altering the content of the file, and without changing the 
    hash value. Similarly, the file's content can be changed without changing the name or extension. However, 
    changing even a single character in the contents of a file changes the hash value of the file.

    The purpose of hash values is to provide a cryptographically-secure way to verify that the contents of a file 
    have not been changed. While some hash algorithms, including MD5 and SHA1, are no longer considered secure 
    against attack, the goal of a secure hash algorithm is to render it impossible to change the contents of a file 
    -- either by accident, or by malicious or unauthorized attempt -- and maintain the same hash value. You can 
    also use hash values to determine if two different files have exactly the same content. If the hash values of 
    two files are identical, the contents of the files are also identical.

    By default, the `Get-FileHash` cmdlet uses the SHA256 algorithm, although any hash algorithm that is supported 
    by the target operating system can be used.

RELATED LINKS
    Online Version: https://learn.microsoft.com/powershell/module/microsoft.powershell.utility/get-filehash?view=powe
    rshell-7.2&WT.mc_id=ps-gethelp
    Format-List 

REMARKS
    To see the examples, type: "Get-Help Get-FileHash -Examples"
    For more information, type: "Get-Help Get-FileHash -Detailed"
    For technical information, type: "Get-Help Get-FileHash -Full"
    For online help, type: "Get-Help Get-FileHash -Online"

    Como essa saída é difícil de ler, você decide usar uma alternativa menos detalhada. Ou seja, você usa o help alias.

  2. Digite o help comando:

    help Get-FileHash

    Agora, uma versão reduzida da saída de ajuda é mostrada. Tem a seguinte aparência:

    NAME
    Get-FileHash

SYNOPSIS
    Computes the hash value for a file by using a specified hash algorithm.

SYNTAX
    Get-FileHash [-InputStream] <System.IO.Stream> [[-Algorithm] {SHA1 | SHA256 | SHA384 | SHA512 | MD5}] 
    [<CommonParameters>]

    Get-FileHash [-LiteralPath] <System.String[]> [[-Algorithm] {SHA1 | SHA256 | SHA384 | SHA512 | MD5}] 
    [<CommonParameters>]

    Get-FileHash [-Path] <System.String[]> [[-Algorithm] {SHA1 | SHA256 | SHA384 | SHA512 | MD5}] 
    [<CommonParameters>]

DESCRIPTION
    The `Get-FileHash` cmdlet computes the hash value for a file by using a specified hash algorithm. A hash value 
    is a unique value that corresponds to the content of the file. Rather than identifying the contents of a file 
    by its file name, extension, or other designation, a hash assigns a unique value to the contents of a file. 
    File names and extensions can be changed without altering the content of the file, and without changing the 
    hash value. Similarly, the file's content can be changed without changing the name or extension. However, 
    changing even a single character in the contents of a file changes the hash value of the file.

    The purpose of hash values is to provide a cryptographically-secure way to verify that the contents of a file 
    have not been changed. While some hash algorithms, including MD5 and SHA1, are no longer considered secure 
    against attack, the goal of a secure hash algorithm is to render it impossible to change the contents of a file 
    -- either by accident, or by malicious or unauthorized attempt -- and maintain the same hash value. You can 
    also use hash values to determine if two different files have exactly the same content. If the hash values of 
    two files are identical, the contents of the files are also identical.

    By default, the `Get-FileHash` cmdlet uses the SHA256 algorithm, although any hash algorithm that is supported 
    by the target operating system can be used.

    Você pode percorrer os resultados verticalmente, linha por linha, usando as teclas de seta. Para visualizar os resultados página por página, use a Barra de espaço.

  3. Executar help Get-FileHash -Examples:

    help Get-FileHash -Examples

    A saída se parece com o seguinte texto:

    NAME
    Get-FileHash

SYNOPSIS
    Computes the hash value for a file by using a specified hash algorithm.


    --------- Example 1: Compute the hash value for a file ---------

    Get-FileHash /etc/apt/sources.list | Format-List

    Algorithm : SHA256
    Hash      : 3CBCFDDEC145E3382D592266BE193E5BE53443138EE6AB6CA09FF20DF609E268
    Path      : /etc/apt/sources.list


    ------ Example 2: Compute the hash value for an ISO file ------

    Get-FileHash C:\Users\user1\Downloads\Contoso8_1_ENT.iso -Algorithm SHA384 | Format-List

    Algorithm : SHA384
    Hash      : 20AB1C2EE19FC96A7C66E33917D191A24E3CE9DAC99DB7C786ACCE31E559144FEAFC695C58E508E2EBBC9D3C96F21FA3
    Path      : C:\Users\user1\Downloads\Contoso8_1_ENT.iso

    Esta saída contém uma lista de exemplos que usam o cmdlet. Localize a parte da resposta que contém o texto Example 1. Esta parte do texto mostra como você pode usar Get-FileHash com um caminho de arquivo canalizando-o para o cmdlet Format-List.

    Gorjeta

    Para ver rapidamente um exemplo, adicione o sinalizador -Examples quando procurar ajuda.