PowerShell vs Bash

2021-06-21 this page is no longer maintained. Content has been expanded with more detail and categorized. See the navigation panel at index page: PowerShell Tutorial. For linux commands, see Linux: Basic Shell Commands

This pages shows the common tasks in both bash and PowerShell.

Simple Commands

The following bash commands have PowerShell alias. (but the options are not the same)

• cd • pwd • ls • pushd • popd • cp • rm • rmdir • mv • cat • echo • set • ps • kill • clear • man

New File

touch name

new-item name -ItemType "file"

New Directory

mkdir name

mkdir name
# full syntax
new-item name -ItemType directory

Copy Directory

cp -r sourceDir destDir

cp -r sourceDir destDir

# full syntax:

# copy all dir's content, including all subdirs
Copy-Item -Recurse -Path "c:/Users/john/abc/*" -Destination "f:/my_backup/"

# copy dir and subdirs, including the dir in destination
Copy-Item -Recurse -Path "c:/Users/john/abc/" -Destination "f:/my_backup/"

Directory Size

# current dir size, in kilo bytes. includes subdirs
du . -sk

# size of current dir (counting subdir)
$size = gci -Recurse | Measure-Object -Property Length -sum

# in megabytes, round to 2 decimal places
"{0:N2}" -f ($size.sum / [Math]::pow(10,6))

find program

which myCommandName

gcm myCommandName
# full syntax
Get-Command myCommandName

Print File Content

cat fname

cat fname
# full syntax
Get-Content fname

Print First/Last n Lines of File

head -n 50 fname

Get-Content fname | select -first 50

Print last 50 lines of file

tail -n 50 fname

Get-Content fname | select -last 50

Join Files

cat fname1 fname2 > newFileName

Get-Content fname1, fname2 > newFileName

unzip

unzip fname.zip

Expand-Archive fname.zip

List Files by File Name Extension

find . -name "*html"

Get-ChildItem -Recurse -include *html

List Backup Files

find . -name "*~"

Get-ChildItem -Include *~ -Recurse

List Directories

find . -type d

Get-ChildItem -Directory -Recurse

List Files Not Directory

find . -type f

Get-ChildItem -File -Recurse

List Empty Files

find . -size 0

Get-ChildItem -recurse | where {$_.length -eq 0}

List Empty Directories

# list empty dir
Get-ChildItem -Directory -Recurse | Where-Object { $_.GetFileSystemInfos().Count -eq 0 }

# list empty dir
Get-ChildItem -Directory -Recurse | Where-Object { $_.GetFiles().Count -eq 0 } | Where-Object { $_.GetDirectories().Count -eq 0 } | ForEach-Object { $_.FullName }

2021-03-20 haven't studied yet which is more proper.

List File Creation Time

# list file with creation time
Get-ChildItem "c:/Users/john/Pictures/ShareX" | Sort-Object CreationTime | Format-Table Name, CreationTime

# list files whose creation date is greater than x
Get-ChildItem "c:/Users/john/Pictures/ShareX" | Where-Object { $_.CreationTime -gt [datetime]"2014/05/28" } | Sort-Object CreationTime | Format-Table Name, CreationTime

delete file

find . -name "*~" -delete

Get-ChildItem -Recurse -Include *~ | Remove-Item

List Files that Contains Search Text

grep myRegex *html

select-string *html -pattern myRegex -CaseSensitive

Compare Files

# compare if 2 files are the same. Any binary file
cmp f1 f2

# show difference of 2 text files
diff f1 f2

# compare if 2 files are the same and or show their differences.
diff (cat f1) (cat f2)

# full syntax
Compare-Object (Get-Content f1) (Get-Content f2)

diff, sort, get column etc

sort

Sort-Object

uniq

sort -Unique

wc

Measure-Object

empty trash

Clear-RecycleBin

Redirect

# put content in a file
echo "some" > myfile.txt
echo "some more" >> myfile.txt # append

# put content in a file
"some" > myfile.txt
"some more" >> myfile.txt # append

Note that, by default, the PowerShell redirect operator ">" creates files with little endian utf-16 encoding, and lines are hard-wrapped at 80 chars, and line ending uses Windows convention of "\r\n" (ascii 13 and 10).

On unixes, the conventional file encoding is utf-8, and lines are not hard-wrapped (sometimes truncated (deleted) silently), and line ending uses "\n" (ascii 10).

To create unix style output, use out-file, like this:

"1'n2'n3" | out-file -Encoding utf8 -width 999000 myfile.txt

However, the line ending used is still "\r\n". To create unix line ending of just "\n", use:

… | Out-String | %{ $_.Replace("`r`n","`n") } | out-file …

However, the end of the file will still contain a "\r".

thanks to Jeffrey Snover of Microsoft for helping on about 10 of the items. (Jeffrey's the inventor of PowerShell)