Anton's Digital Garden

Bash Equivalents

7 min read

Examples of bash commands and how to do the same thing in PowerShell

Echo

Write text to the screen.

  • Bash

    echo "Hello, World!"
echo -e "Hello, \t World!"

  • PowerShell

    Write-Output 'Hello, World!'
Write-Output "Hello, `t World!"

    Dirty version:
    echo 'Hello, World!'

Execute a Script

Save and execute a script with bash and PowerShell.

  • Bash
    Assume that echo1.sh has the following contents.

    echo "Hello, World!"

    You would the execute it with the following command line.

    bash echo1.sh

  • PowerShell
    Assume echo1.ps1 has the following contents.

    Write-Output "Hello, World!"

    You would then execute it with the following command line.

    pwsh echo1.ps1

Comments

Comments are the same in PowerShell and bash.

  • Bash

    # My Comment!

  • PowerShell

    # My Comment!

Multiline Comments

Multiline comments are different between bash and PowerShell.

  • Bash

    : 'Multi
line
comment'
echo "42"

  • PowerShell

    <# 
Multi
line
comment
#>
Write-Output "42"

While Loop

  • Bash

    valid=true
count=1
while [ $valid ]
do
echo $count
if [ $count -eq 5 ];
then
break
fi
((count++))
done

  • PowerShell

    $count = 0
while ($true) {
  Write-Host $count
  if ($count -eq 5) {
      break
  }
  $count++
}

For Loop

  • Bash

    for (( counter=10; counter>0; counter-- ))
do
echo -n "$counter "
done

  • PowerShell

    for ($counter = 10; $counter -gt 0; $counter--) {
    Write-Host $counter
}

Get User Input

  • Bash

    echo "Enter Your Name"
read name
echo "Welcome, $name!"

  • PowerShell

    $name = Read-Host "Enter Your Name"
Write-Host "Welcome, $name!"

If Statement

  • Bash

    n=10
if [ $n -lt 10 ];
then
echo "It is a one digit number"
else
echo "It is a two digit number"
fi

  • PowerShell

    $n = 10
if ($n -lt 10) {
    Write-Host "It is a one digit number"
} else {
    Write-Host "It is a two digit number"
}

If with And Logic

  • Bash

    echo "Enter username"
read username
echo "Enter password"
read password
 
if [[ ( $username == "admin" &amp;&amp; $password == "secret" ) ]]; then
echo "valid user"
else
echo "invalid user"
fi

  • PowerShell

    $UserName = Read-Host "Enter username"
$Password = Read-Host "Enter password"
 
if ($username -eq 'admin' -and $password -eq 'secret') {
    Write-Host 'valid user'
} else {
    Write-Host 'invalid user'
}

If with Or Logic

  • Bash

    echo "Enter any number"
read n
 
if [[ ( $n -eq 15 || $n  -eq 45 ) ]]
then
echo "You won the game"
else
echo "You lost the game"
fi

  • PowerShell

    [int]$n = Read-Host "Enter any number"
 
if ($n -eq 15 -or $n -eq 45) {
    Write-Host "You won the game"
} else {
    Write-Host "You lost the game"
}

If Else Statements

  • Bash

    echo "Enter your lucky number"
read n
 
if [ $n -eq 101 ];
then
echo "You got 1st prize"
elif [ $n -eq 510 ];
then
echo "You got 2nd prize"
elif [ $n -eq 999 ];
then
echo "You got 3rd prize"
 
else
echo "Sorry, try for the next time"
fi

  • PowerShell

    [int]$n = Read-Host "Enter your lucky number"
 
if ($n -eq 101) {
    Write-Host "You got 1st prize"
} elseif ($n -eq 510) {
    Write-Host "You got 2nd prize"
} elseif ($n -eq 999) {
    Write-Host "You got 3rd prize"
} else {
    Write-Host "Sorry, try for the next time"
}

Case Statement

  • Bash

    echo "Enter your lucky number"
read n
case $n in
101)
echo "You got 1st prize" ;;
510)
echo "You got 2nd prize" ;;
999)
echo "You got 3rd prize" ;;
*)
echo "Sorry, try for the next time" ;;
esac

  • PowerShell

    [int]$n = Read-Host "Enter your lucky number"
switch($n) {
    101 { Write-Host "You got 1st prize" }
    510 { Write-Host "You got 2nd prize" }
    999 { Write-Host "You got 3rd prize" }
    default { Write-Host "Sorry, try for the next time" }
}

Command Line Arguments

  • Bash

    echo "Total arguments : $#"
echo "1st Argument = $1"
echo "2nd argument = $2"

  • PowerShell

    Write-Host "Total arguments: $($args.Length)"
Write-Host "1st Argument: $($args[0])"
Write-Host "2nd Argument: $($args[1])"

Named Command Line Arguments

  • Bash

    for arg in "$@"
do
index=$(echo $arg | cut -f1 -d=)
val=$(echo $arg | cut -f2 -d=)
case $index in
X) x=$val;;
 
Y) y=$val;;
 
*)
esac
done
((result=x+y))
echo "X+Y=$result"

  • PowerShell

    param([int]$X, [int]$Y)
 
$Result = $X + $Y
Write-Host "X+Y=$Result"

Concatenating Strings

  • Bash

    string1="Linux"
string2="Hint"
echo "$string1$string2"
string3=$string1+$string2
string3+=" is a good tutorial blog site"
echo $string3

  • PowerShell

    $string1 = "Ironman"
$string2 = "Software"
Write-Host "$string1$string2"
$string3 = $string1+$string2
$string3 +=" makes good software"
Write-Host $string3

Substring of a String

  • Bash

    Str="Learn Linux from LinuxHint"
subStr=${Str:6:5}
echo $subStr

  • PowerShell

    $Str = 'Learn PowerShell from Ironman Software'
$subStr = $Str.Substring(6, 10)
Write-Host $subStr

Functions

  • Bash

    function F1()
{
echo 'I like bash programming'
}
 
F1

  • PowerShell

    function F1 {
    Write-Host "I like PowerShell programming"
}
F1

Functions with Parameters

  • Bash

    Rectangle_Area() {
area=$(($1 * $2))
echo "Area is : $area"
}
 
Rectangle_Area 10 20

  • PowerShell

    function RectangleArea {
    $Area = $Args[0] * $Args[1]
    Write-Host "Area is: $Area"
}
RectangleArea 10 20

Use the Return value of a Function

  • Bash

    function greeting() {
 
str="Hello, $name"
echo $str
 
}
 
echo "Enter your name"
read name
 
val=$(greeting)
echo "Return value of the function is $val"

  • PowerShell

    function Greeting {
    "Hello, $Name"
}
 
$Name = Read-Host "Enter your name"
$Val = Greeting
Write-Host "Return value of the function is $val"

Make a Directory

  • Bash

    echo "Enter directory name"
read newdir
`mkdir $newdir`

  • PowerShell

    $newdir = Read-Host "Enter directory name"
New-Item $newdir -ItemType Directory

    Dirty version:
    mkdir $newdir

Make Directory if it doesn’t exist

  • Bash

    echo "Enter directory name"
read ndir
if [ -d "$ndir" ]
then
echo "Directory exist"
else
`mkdir $ndir`
echo "Directory created"
fi

  • PowerShell

    $newdir = Read-Host "Enter directory name"
if (Test-Path $newdir)
{
    Write-Host "Directory exists"
} else {
    New-Item $newdir -ItemType Directory
}

    Dirty version:
    $newdir = Read-Host "Enter directory name"
    if (gi $newdir -ea si)
    {
        echo "Directory exists"
    } else {
        mkdir $newdir
    }

Read a File

  • Bash

    file='book.txt'
while read line; do
echo $line
done < $file

  • PowerShell

    Get-Content 'book.txt'

Delete a File

  • Bash

    echo "Enter filename to remove"
read fn
rm -i $fn

  • PowerShell

    $fn = Read-Host "Enter a file to remove"
Remove-Item $fn

    Dirty version:
    $fn = Read-Host "Enter a file to remove"
    rm $fn

Append to a File

  • Bash

    echo "Before appending the file"
cat book.txt
 
echo "Learning Laravel 5">> book.txt
echo "After appending the file"
cat book.txt

  • PowerShell

    Write-Host "Before appending the file"
Get-Content book.txt
 
"Learning Laravel 5" >> book.txt
Write-Host "After appending the file"
Get-Content book.txt

Wait for a Process

  • Bash

    echo "Wait command" &amp;
process_id=$!
wait $process_id
echo "Exited with status $?"

  • PowerShell

    Start-Process notepad -Wait
Get-Process -Id $ProcessId | Wait-Process

Sleep

  • Bash

    echo “Wait for 5 seconds”
sleep 5
echo “Completed”

  • PowerShell

    Write-Host "Wait for 5 seconds"
Start-Sleep 5

    Dirty version:
    sleep 5
    Write-Host "Completed"

Download Files

  • Bash

    curl -o newname.txt http://www.het.brown.edu/guide/UNIX-password-security.txt

  • PowerShell

    Invoke-WebRequest http://www.het.brown.edu/guide/UNIX-password-security.txt -OutFile .\newname.txt

    Dirty version:
    iwr http://www.het.brown.edu/guide/UNIX-password-security.txt -o newname.txt

Search a File for a String

  • Bash

    error log.txt     # Search a file
grep error *      # Search a directory
grep -r error *   # Recursively search a directory
grep -l error *   # List matching files
grep -c error *   # Measure number of objects
grep -C 2 error * # Display lines before and after

  • PowerShell

    Select-String error log.txt                     # Search a file
Select-String error *                           # Search a Directory
Get-ChildItem * -Recurse | Select-String error  # Recursively search a directory
Select-String error * | Select-Object path      # List matching files
Select-String error * | Measure-Object          # Count Matches
Select-String error *                           # Display lines before and after

Sources:

Related: Shell, Bash - The Linux command line

Tags: PowerShell - A command-line shell and scripting language to manage Windows system and automate administrative tasks

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