Below is a list of common File Extensions and FileTypes. These can be viewed and modified with ASSOC and FTYPE.
.aac .ac3 .accountpicture-ms="accountpicturefile" .acl="ACLFile" .bmp="Paint.Picture" .cab="CABFolder" .chk="chkfile" .cmd="cmdfile" .cpl="cplfile" .css="CSSfile" .csv .dll="dllfile" .doc="Word.Document.8" .docx="Word.Document.12" .fon="fonfile" .gif="giffile" .gz .hlp="hlpfile" .hol="Outlook.File.hol.15" .htm .html .ico="icofile" .img="Windows.IsoFile" .ini="inifile" .iso="Windows.IsoFile" .jpe="jpegfile" .jpeg="jpegfile" .jpg="jpegfile" .js="JSFile" .lnk="lnkfile" .log="txtfile" .mp3 .mp4 .msi="Msi.Package" .pdf .png="pngfile" .potx="PowerPoint.Template.12" .pps="PowerPoint.SlideShow.8" .pptx="PowerPoint.Show.12" .ps1="Microsoft.PowerShellScript.1" .reg="regfile" .scr="scrfile" .symlink=".symlink" .tar .theme="themefile" .tif="TIFImage.Document" .tiff="TIFImage.Document" .ttf="ttffile" .txt="txtfile" .URL="InternetShortcut" .vbs="VBSFile" .vhd="Windows.VhdFile" .wav .xaml="Windows.XamlDocument" .xls="Excel.Sheet.8" .xlsm="Excel.SheetMacroEnabled.12" .xlsx="Excel.Sheet.12" .xml="xmlfile" .xsl="xslfile" .zip="CompressedFolder"
“Every country is like a particular type of person. America is like a belligerent, adolescent boy; Canada is like an intelligent, 35-year-old woman. Australia is like Jack Nicholson. It comes right up to you and laughs very hard in your face in a highly threatening and engaging manner” ~ Douglas Adams
ASSOC - Change file extension associations.
FTYPE - Edit file types (used in file extension associations).