Subchapter 57.1

Batch Files And Functions

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Batch Files, Scripts, and Functions

Utility Scripts

Batch Files And Functions · Batch Files · github/awesome-copilot · Skills Docs

SET /A Arithmetic — SET /A supports add (+), subtract (-), multiply (*), integer divide (/), modulo (%%), bit-shift (<<, >>), bitwise AND (&), OR (|), XOR (^), NOT (~), logical NOT (!), grouping (), and combined assignment operators (+=, -=, *=, /=, %%=, &=, |=, ^=, <<=, >>=). Numeric literals: octal prefix 0, hex prefix 0x. 32-bit signed integer limit (−2,147,483,648 to 2,147,483,647); 16-bit on NT4. No exponentiation operator — use a loop multiplying in a variable. No square root — use binary search or PowerShell.
No Floating Point — Batch has no native floating-point. Workaround: multiply by 100 (or 1000), do integer math, then extract whole and fraction parts via string slicing: SET Whole=%Result:~0,-2% and SET Frac=%Result:~-2%. For truly large or precise math, embed a PowerShell one-liner: powershell -C "expression".
Big Number Workarounds — For numbers exceeding 32-bit range: (1) chop last N digits for approximate math, (2) split into individual digits for arbitrary-precision add/multiply (e.g., process digit-by-digit with carry), (3) call PowerShell or another language.
Formatting Numbers — Display hex: repeatedly divide by 16, index into 0123456789ABCDEF helper string using !Convert:~%Digit%,1!. Display octal: divide by 8 loop. Right-align decimals: pad with spaces then chop with !Align:~-8!. File size limit ~107MB when multiplying by 20 (32-bit overflow). PowerShell .ToString("format") is simpler for complex formatting.
Boolean Logic in Conditions — No AND/OR/XOR for IF conditions (only for binary math via SET /A). AND: nested IF statements. OR: set a temp variable to 0, set to 1 per matching condition, then test. XOR: too complex with nested IF. Better approach: assign each condition to a binary variable (0 or 1), then use SET /A "ResultAND = %C1% & %C2%", SET /A "ResultOR = %C1% | %C2%", SET /A "ResultXOR = %C1% ^ %C2%".
Leading Zeroes Gotcha — SET /A treats numbers with leading 0 as octal, so SET /A x=08 and SET /A x=09 cause “invalid number” errors. Always strip leading zeroes before arithmetic. Common techniques: use FOR /F tokenizing, string manipulation to remove leading zeroes, or SET /A "1%var:~-2% - 100" pattern to force decimal interpretation.

Rename Files — REN oldname newname supports wildcards: REN *.txt *.bak. Undocumented: REN file.txt *s chops the filename after the last occurrence of the character. Use FOR loops for complex renaming: FOR %%A IN (*.txt) DO REN "%%A" "%%~nA_backup%%~xA". Rename folders with MOVE oldfolder newfolder.
File Properties via FOR Modifiers — FOR %%A IN (file) DO with modifiers: %%~nA (name), %%~xA (extension), %%~snA (short 8.3 name), %%~aA (attributes), %%~dA (drive), %%~zA (size bytes), %%~tA (date/time), %%~dpA (drive+path/parent), %%~fA (full qualified path), %%~$PATH:A (first PATH match). Modifiers are combinable: %%~nxA (name+ext), %%~dpnxA (full path), %%~fsA (full short path).
File and Product Versions — FILEVER /V filename (from Support Tools) displays file/product version, description, company. Extract version with FOR /F: parse the /V output. Comparing dotted version strings: compare each segment numerically (string comparison of 1.10 vs 1.9 fails because "10" < "9" alphabetically).
START and File Associations — START "title" [/D path] [/I] [/MIN] [/MAX] [/WAIT] [/B] [/SEPARATE] [/SHARED] [priority] command [args]. Priority classes: /LOW, /NORMAL, /HIGH, /REALTIME, /ABOVENORMAL, /BELOWNORMAL. File associations via HKEY_CLASSES_ROOT: parameters %1 (file path), %L (long name), %W (working directory). PATHEXT controls which extensions are resolved without explicit extension.
Temporary Files — Use "%TEMP%.\tempfile" (with trailing dot) for safe temp paths. Windows 2000 %TEMP% often contains spaces — always quote. RUNAS may change %TEMP% to a read-only location. Create unique temp names with %RANDOM% or %TIME::=%.
PDF Commands — Get page count: ExifTool (-PageCount), GhostScript (gswin32c -q -dNODISPLAY -c "(file) (r) file runpdfbegin pdfpagecount = quit"), PDFtk (pdftk file dump_data | FIND "NumberOfPages"), or native: TYPE file.pdf | FINDSTR /R /C:"/Type\s*/Page" (approximate). Merge: GhostScript or pdftk file1.pdf file2.pdf cat output merged.pdf. Print: Acrobat Reader /P or /T, Foxit /p, GhostScript, or registered print command.
Check Folder Exists — NT: IF EXIST "folder\" (trailing backslash). DOS: IF EXIST folder\NUL. More robust: PUSHD "folder" && (POPD & ECHO exists) || ECHO not exists. The NUL trick may fail with junctions/symlinks in NT. FOR /D can also match directories: FOR /D %%A IN (folder) DO ECHO found.
FOR /D and FOR /R — FOR /D %%A IN (pattern) DO command matches directories. FOR /R [path] %%A IN (pattern) DO command walks directory trees recursively. Combine: FOR /R "C:\" /D %%A IN (*) DO ECHO %%A lists all subdirectories.
RD (RMDIR) — RD /S /Q directory removes directory tree silently. /S removes all subdirectories and files. /Q suppresses confirmation. Returns errorlevel 2 if directory not found, 145 if directory not empty (when /S omitted).
Wildcards Quirks — * matches any characters including none; ? matches exactly one character. Quirks: wildcards after the 3rd character of the extension are ignored in some commands. Short 8.3 names can cause unexpected matches (a file with a long name may match via its short name). DIR *~*.* returns unpredictable results. DEL *~*.* is dangerous — may delete unexpected files due to short name matching.

FOR /F (File/String/Command Parsing) — FOR /F "options" %%A IN (source) DO command. Options: tokens= (column selection, e.g., 1,3*), delims= (delimiter chars, default space/tab), eol= (comment char, default ;), skip=n (skip first N lines), usebackq (changes quoting: back-quotes for commands, double-quotes for filenames, single-quotes for strings). Sources: filename, "string", `command` (with usebackq), or ('command'). Variable modifiers: %%~fA (full path), %%~dpA (drive+path), etc.
Tokens and Delims — tokens=1,3 extracts columns 1 and 3 into %%A and %%B. tokens=2* gets column 2 in %%A and remainder in %%B. tokens=1-5 gets columns 1–5. Default delimiters: space and tab. delims=,; sets comma and semicolon. delims= (nothing) reads the entire line. eol= must be set to empty (or a char not in data) to avoid skipping lines starting with ;.
Redirection — > (overwrite stdout), >> (append stdout), 2> (redirect stderr), 2>&1 (merge stderr into stdout), 1>&2 (stdout to stderr), | (pipe stdout). File handles: 0=stdin, 1=stdout, 2=stderr. Place redirection before the command for readability: >file ECHO text. Escape with caret: ECHO text ^> not-redirected. Space before > may get echoed as part of the text.
Streams and Redirection Explained — Three standard streams: Standard Output (handle 1), Standard Error (handle 2), Console (CON). 2>&1 merges stderr into stdout for combined piping/capture. >CON bypasses file redirection and always writes to console. Console output from CLS and some commands cannot be redirected. Best practice: command > logfile 2>&1 to capture both streams. Ambiguity: lines ending in 1 or 2 before > may be misinterpreted as handle numbers.
TEE Equivalent — No native TEE in Windows. Workaround: pipe to a batch/PowerShell script that writes to both screen and file. Or use port of Unix TEE command. Simple batch approximation: use FOR /F to read command output, ECHO to screen and >>file simultaneously.
Detect File Encoding — FOR /F loop aborts on ASCII 0 (null) characters present in Unicode files. Test: FOR /F %%A IN (file) DO (ECHO ANSI&GOTO:EOF) — if the loop completes without the ECHO executing, the file is Unicode (contains null bytes that break FOR /F).
ASCII vs. Unicode Conversion — TYPE does not lock files (useful for copying logs in use). Unicode to ASCII: TYPE unicode.txt > ascii.txt. ASCII to Unicode: CMD /U /C TYPE ascii.txt > unicode.txt. Unicode BOM header: bytes 0xFF 0xFE. Convert Unix linefeeds to Windows: TYPE input.txt | MORE /E /P > output.txt.
Base64 Encoding/Decoding — CERTUTIL.EXE -encode inputfile outputfile.b64 (encode to Base64). CERTUTIL.EXE -decode inputfile.b64 outputfile (decode from Base64). Output includes header/footer lines (-----BEGIN CERTIFICATE----- / -----END CERTIFICATE-----) that may need stripping with FINDSTR /V "CERTIFICATE".
Hex Encoding/Decoding — CERTUTIL.EXE -encodehex inputfile outputfile [format]. Formats: default (hex editor view with offsets and ASCII), 4 (hex only, no ASCII or offsets), 12 (single continuous hex line). Decode: CERTUTIL.EXE -decodehex hexfile outputfile. PowerShell alternatives: [Convert]::ToHexString() / [Convert]::FromHexString() (.NET 5+).
File Hashes — CERTUTIL.EXE -hashfile filename [algorithm]. Algorithms: MD2, MD4, MD5, SHA1 (default), SHA256, SHA384, SHA512. Example: CERTUTIL -hashfile myapp.exe SHA256. Alternative: FCIV (File Checksum Integrity Verifier, unsupported Microsoft tool, MD5/SHA1 only). PowerShell: Get-FileHash -Algorithm SHA256 filename.

Get Default Browser — Manual: START ms-settings:defaultapps. Programmatic: read HKCU\SOFTWARE\Microsoft\Windows\Shell\Associations\UrlAssociations\http\UserChoice\ProgID via REG QUERY, returns a value like FirefoxHTML-308046B0AF4A39CB. Then look up the executable: REG QUERY "HKCR\<ProgID>\shell\open\command" to get the browser path. Old techniques using ASSOC .html / FTYPE no longer work reliably in Windows 10+.
Auto-Download Prompt — Check if a third-party tool exists: TOOL /? >NUL 2>&1 then IF ERRORLEVEL 1 means missing. If tool returns non-zero on /?, use (TOOL /? 2>&1) | FIND /I "copyright" >NUL to detect its output. Prompt user: SET /P Download=Download now? [y/N], then IF /I "%Download%"=="Y" START "title" "https://download-page". Always detect before executing to avoid cryptic not recognized errors.
E-mail from Batch — START mailto:user@example.com?subject=Hello%%20World^&body=Message%%20text. Escaping: spaces=%%20, CR/LF=%%0D%%0A, ampersands escaped with caret (^&), double %% for batch. Length limited to max command line (~8191 chars on modern Windows). Only creates the message — user must press Send. For unattended sending: use third-party tools like Blat (SMTP, free) or MailSend (shareware). HTML5 also supports <a href="tel:"> and <a href="sms:">.
FTP Scripting — FTP -s:scriptfile hostname for unattended transfers. Script file contains: USER username, password (next line), cd path, binary, prompt n, mget *.* (or mput). Security: create script on-the-fly with ECHO redirection, delete after use (TYPE NUL >script.ftp & DEL script.ftp). Check for errors: redirect FTP output to log file, use FIND to search for error messages. Alternatives: WGET (wget ftp://host/file for anonymous downloads), WinSCP (SFTP/FTP with scripting interface), ScriptFTP (encrypted scripts, self-contained executables).
WMIC (WMI Command Line) — Available XP Pro+ (disabled by default in Windows 11). Commands: GET (read properties), SET (change), CALL (invoke methods). Output formats: /Format:csv, /Format:list, /Format:htable. Store in variables: FOR /F "tokens=*" %%A IN ('WMIC BIOS Get Manufacturer^,Name /Value ^| FIND "="') DO SET BIOS.%%A. WHERE clause with WQL: WMIC Path Win32_NetworkAdapter Where "PhysicalAdapter=TRUE" Get. Aliases vs full class path: WMIC OS Get = WMIC Path Win32_OperatingSystem Get. Remote: /Node:computer. Non-default namespace: /NameSpace:\\root\other. Registry access possible but REG.EXE is easier.
DMIDecode — Linux/Unix utility ported to Windows for reading DMI/SMBIOS data (hardware info like BIOS, system, baseboard, chassis, processor details) directly from firmware tables without WMI.
RAS (Remote Access) — Commands for managing dial-up and VPN connections from the command line. RASDIAL entryname [username password] to connect, RASDIAL /DISCONNECT to disconnect. RASPHONE -h entryname to hang up.
Terminal Server Commands — QUERY USER [/SERVER:name] (list sessions), QUERY SESSION, LOGOFF sessionid /SERVER:name, TSSHUTDN seconds /SERVER:name /POWERDOWN /DELAY:n /V (shutdown with notification), MSG sessionid message, SHADOW sessionid (remote control). Use CHANGE LOGON /DISABLE to prevent new logons.

Print Text Files — Classic: PRINT myfile.txt /D:LPT1 (requires LPT/COM port). Modern: NOTEPAD /P file.txt (default printer, any text file regardless of association). Wordpad: WRITE /P file.rtf (with print dialog) or WRITE /PT file.rtf PrinterName (silent, specific printer).
Print Registered File Types — Technique: use ASSOC .ext to get the file type, then look up the print command in HKCR\FileType\shell\print\command. HTML: RUNDLL32.EXE MSHTML.DLL,PrintHTML "%1". PDF: read association from registry, extract print command via REGEDIT /E or REG QUERY. For any registered type: query HKCR\filetype\shell\print\command and execute with START /MIN. File association parameters: %1 (full path), %L (long name), %W (parent folder).
Command-Line Switches for Applications — Extensive collection of print/open/convert switches: Adobe Reader (/P print dialog, /N /T file printer silent print), Foxit Reader (/p silent, /t file printer), IrfanView (/print, /convert=output), OpenOffice (-pt "Printer" file), Word (requires VBA macro winword /mPrintDefault /q /n), Notepad (/P), Wordpad (/P, /PT), PowerPoint (/PT "Printer" "" "" "File"). Most programs accept the file path as first argument to open it.
Command-Line Printer Control (PRINTUI.DLL) — RUNDLL32.EXE PRINTUI.DLL,PrintUIEntry [options] (Windows 7 shorthand: PRINTUI.EXE [options]). Install printer: /if /b "Name" /f ntprint.inf /r "port:" /m "Model". Delete: /dl /n "Name". Set default: /y /n "Name". Get/set settings: /Xg / /Xs. Backup: /Ss /n "printer" /a "file.dat". Restore: /Sr /n "printer" /a "file.dat". Always returns errorlevel 0 — verify success by exporting settings to file and checking existence. Migrate printers: PrintMig 3.1 (W2K/XP/2003) or PRINTBRM (W7/2008+).
DDE Command-Line Control — Programs that act as DDE servers can be controlled from the command line using DDE commands. Tools like CMCDDE and ClassExec send DDE execute/request commands to running applications. Useful for controlling Office apps that lack direct print commands.
Printer Management Scripts — Windows ships with VBScript printer management scripts in %windir%\System32\ (pattern *prn*.vbs): prnmngr.vbs (add/delete/list printers), prncnfg.vbs (configure), prnport.vbs (manage ports), prndrvr.vbs (manage drivers), prnjobs.vbs (manage print jobs).

Conditional Execution — IF condition command. IF ... ELSE requires parentheses: IF condition (cmd1) ELSE (cmd2). IF ... ELSE IF chains via: IF cond1 (cmd1) ELSE IF cond2 (cmd2) ELSE (cmd3). Command chaining: & (always sequential), && (execute next only on success/errorlevel 0), || (execute next only on failure/non-zero errorlevel). Combine: (cmd1 && cmd2 && cmd3) || ECHO Error occurred. Logical AND in conditions: nested IF. Logical OR: set temp variable per condition, test final value.
FOR Loops (DOS and NT) — Basic: FOR %%A IN (set) DO command. FOR /D %%A IN (pattern) DO (directories only). FOR /R [path] %%A IN (pattern) DO (recursive tree walk). FOR /L %%A IN (start,step,end) DO (numeric range). FOR /F "options" %%A IN (source) DO (parse files/strings/commands). At command prompt use %A; in batch files use %%A. Variables are single-letter, case-sensitive (%%A ≠ %%a).
FOR /F Details — tokens=1,3* extracts columns 1 and 3 into %%A/%%B, remainder into %%C. delims=,; sets delimiters. eol= (comment character). skip=n (skip header lines). usebackq enables back-quoted commands and double-quoted filenames. Variable modifiers: %%~fA (full path), %%~dpA (drive+path), %%~nxA (name+ext), %%~zA (file size), %%~tA (timestamp), %%~aA (attributes), %%~$PATH:A (search PATH). Modifiers are combinable.
File Attributes in FOR — %%~aA expands to a string of attribute flags like d-------- (directory) or --a------ (archive). Attribute positions: d (directory), r (read-only), a (archive), h (hidden), s (system), plus compressed, encrypted, etc. Test with IF "%%~aA" GEQ "d" ECHO directory or parse specific character positions.
Extended FOR Variables — Punctuation characters can serve as FOR variable names: %%~f#, %%~dp$PATH:!, etc. This allows nested FOR loops without running out of letter variables. Numbers as FOR variables: %%0–%%9 and %%~f0 etc. work in some contexts but conflict with batch parameters %0–%9.
Mimic While Loops — Do…Until: :Loop / do work / IF NOT condition GOTO Loop. Do…While: :Loop / IF condition GOTO End / do work / GOTO Loop / :End. Use unique label names with numeric suffixes (:Loop1, :Loop2) to avoid conflicts.
GOTO — GOTO label jumps to :label. GOTO:EOF exits the current subroutine (or batch file if not in a CALLed subroutine). Labels are case-insensitive. Only the first 8 characters of a label are significant in some Windows versions. GOTO inside a parenthesized code block (like FOR or IF) breaks out of that block.
Continuous FOR /L Loops — FOR /L %%A IN (1,0,1) DO command creates an infinite loop (step=0, never reaches end). Also: FOR /L %%A IN () DO or very large end values. Useful for polling/waiting scenarios.
Breaking Endless Loops — Ctrl+C sends break signal. From another process: TASKKILL /F /IM cmd.exe /FI "WINDOWTITLE eq BatchTitle". Self-breaking: check a flag file or registry value each iteration, IF EXIST stop.flag GOTO End.
Errorlevels — IF ERRORLEVEL n is TRUE if errorlevel >= n (not equal!). Exact test: IF %ERRORLEVEL% EQU 0 (or NEQ, GTR, LSS). Never create a variable named ERRORLEVEL (shadows the dynamic pseudo-variable). Set errorlevel: EXIT /B n (W2K+, exits batch/subroutine and sets errorlevel to n). Reset to 0: CMD /C EXIT 0 or VER >NUL. Force non-zero: COLOR 00 (sets errorlevel 1) or VERIFY OTHER 2>NUL (sets errorlevel 1). For exact errorlevel checking in DOS: reverse-order IF ERRORLEVEL chain (check highest first).
EXIT — EXIT closes the CMD window entirely. EXIT /B [exitcode] exits only the current batch file (or subroutine if called via CALL) and optionally sets %ERRORLEVEL% to exitcode. Always use EXIT /B in batch files to avoid closing the user’s terminal. In subroutines: EXIT /B 0 for success, EXIT /B 1 (or other non-zero) for failure.

DATE and TIME Basics in NT — Get current date/time: FOR /F "tokens=*" %%A IN ('DATE /T') DO SET Today=%%A or use built-in %Date% and %Time% variables (W2K+). Inner FOR loop strips day-of-week prefix. Values are locale-dependent (order of day/month, separators, AM/PM vs 24h all depend on regional settings).
Parsing DATE and TIME — Two approaches: FOR /F with delimiters (FOR /F "tokens=1-3 delims=/-" %%A IN ("%Today%") DO ...) or SET substring (SET Year=%Today:~-4%, SET Month=%Today:~-10,2%). Determine date order via registry: read iDate (0=MDY, 1=DMY, 2=YMD) and sDate (separator) from HKCU\Control Panel\International using REG QUERY. Parse time with leading zeros: SET Now=%Time: =0% then SET Hours=%Now:~0,2%. Strip leading zeros: SET /A Hours = 100%Hours% %% 100.
Advanced Date Math — Convert dates to Julian day numbers for arithmetic. Fliegel-Van Flandern algorithm in batch (by Ron Bakowski): :JDate subroutine takes YYYY MM DD, returns Julian date. :GDate converts back. Date arithmetic: SET /A JPast = JDate - 28 gives date 4 weeks ago. Weekday from Julian: SET /A WD = %JDate% %% 7 (0=Monday…6=Sunday). Age in days: subtract birth Julian from today’s Julian.
Read the CMOS Real Time Clock — Use DEBUG to read CMOS RTC registers directly (16-bit only, requires 32-bit OS). Port 70 selects register, port 71 reads value. Registers: 09=year, 08=month, 07=day, 04=hours, 02=minutes, 00=seconds (all BCD). Register 0E > 7F means clock not set. 100% locale-independent but requires admin privileges.
Delays and Wait Techniques — PAUSE waits for any key. SLEEP n (Resource Kit) waits n seconds. TIMEOUT /T n (native W7+) waits n seconds or keypress; /NOBREAK requires Ctrl+C. PING trick: PING localhost -n 6 >NUL delays ~5 seconds (n=seconds+1). CHOICE trick: REM | CHOICE /C:AB /T:A,10 >NUL (DOS) or CHOICE /C:AB /D:A /T:10 >NUL (W10). PowerShell: powershell -Command "Start-Sleep -Seconds %1".
The AT Command — Schedule commands at absolute times (NT Server): AT [\\computername] time [/INTERACTIVE] [/EVERY:day,...] command. Uses SYSTEM account by default. Batch files must be preceded with CMD /C. Debug scheduled tasks: schedule CMD.EXE with /INTERACTIVE to get a visible prompt in the SYSTEM context. Superseded by SCHTASKS in Windows XP+.
JT (Job Tool) — Windows 2000 Resource Kit tool for Task Scheduler command line management. Enumerate tasks: JT /SE or JT /SE P for full details. Add, edit, or remove scheduled jobs on local/remote computers. Command line switches are unintuitive; use JTHelp.bat to generate HTML help.
SCHTASKS — Full-featured task scheduler CLI (XP+). Subcommands: /Create (schedule new task), /Delete, /Query, /Change, /Run (run immediately), /End (stop running task), /ShowSid. Create example: SCHTASKS /Create /SC DAILY /TN "MyTask" /TR "C:\script.bat" /ST 21:00. Schedule types: MINUTE, HOURLY, DAILY, WEEKLY, MONTHLY, ONCE, ONSTART, ONLOGON, ONIDLE, ONEVENT. Use /RU for run-as account, /XML for import/export, /F to force overwrite.

User Input — SET /P variable=prompt (W2K+) reads a line of user input. Warning: input containing &, <, >, | or " can cause code injection—never use SET /P in elevated scripts. NT4: FOR /F "tokens=*" %%A IN ('TYPE CON') DO SET INPUT=%%A (user presses F6+Enter to finish). MS-DOS: CHOICE /C:YN for single-key Yes/No. PowerShell login dialog: FOR /F "tokens=1* delims=;" %%A IN ('PowerShell ./login.ps1 %UserName%') DO (SET Usr=%%A & SET Pwd=%%B).
Neat Dialog Boxes in Batch Files — C# GUI utilities for batch: MessageBox.exe (popup message, returns clicked button caption), InputBox.exe (text input with optional password masking, regex filtering, timeout), OpenFileBox.exe / SaveFileBox.exe (file dialogs), OpenFolderBox.exe (folder browser), PrinterSelectBox.exe, DateTimeBox.exe, DropDownBox.exe / RadioButtonBox.exe (list selection), MultipleChoiceBox.exe (checkboxes), ColorSelectBox.exe, FontSelectBox.exe, ProgressBarGUI.exe. All write selection to stdout for FOR /F capture. Return errorlevel 0=OK, 2=Cancel.
Hide or Minimize the Console — Start minimized: START /MIN "title" "batch.bat". Minimize own window: CONSOLESTATE /Min or SETCONSOLE /minimize or title+CMDOW combo. Hide own window: CONSOLESTATE /Hide or SETCONSOLE /hide. Completely hidden (no flash): launch via RUNNHIDE.EXE batch.bat or WSCRIPT.EXE RunNHide.vbs batch.bat or HSTART /NOCONSOLE "batch.bat". Note: hiding from within the batch always shows a brief console flash; cloaking must start before the batch.
Error Messages in Local Language — NET HELPMSG nnnn displays Windows error message number nnnn in the local system language. Generate a complete list: FOR /L %%A IN (0,1,16384) DO (FOR /F "tokens=*" %%B IN ('NET HELPMSG %%A 2^>NUL') DO ECHO %%A %%B). Use these numbers in batch scripts for localized error output without hardcoding translations.
Popup Messages — MSG.EXE (XP Pro+): send popup to users/sessions. VBScript on-the-fly: > msg.vbs ECHO WScript.Echo "message" then WSCRIPT msg.vbs. MSHTA one-liner: MSHTA vbscript:Close(MsgBox("message",vbOKOnly,"title")). PowerShell one-liner: FOR /F "usebackq" %%A IN (\PowerShell -Command “Add-Type -AssemblyName System.Windows.Forms; [System.Windows.Forms.MessageBox]::Show(‘message’,’title’,’YesNo’,’Question’)”`) DO SET Answer=%%A`. Result is button caption string (Yes, No, OK, Cancel).
ANSI Colors and Escape Sequences — ANSI.SYS required in DOS; built into Windows 10+ CMD.EXE natively. Escape character = ASCII 27. Insert in batch via FORFILES: FORFILES /P %~dps0 /M %~nxs0 /C "CMD /C ECHO 0x1B[1;31m Red Text 0x1B[0m". Color codes: <Esc>[30m–<Esc>[37m foreground, <Esc>[40m–<Esc>[47m background, <Esc>[1;3Xm bright. Attributes: <Esc>[0m reset, <Esc>[1m bold, <Esc>[4m underline, <Esc>[7m reverse. Cursor: <Esc>[r;cH position, <Esc>[nA/B/C/D move, <Esc>[2J clear screen, <Esc>[K clear to end of line. In PROMPT strings use $E instead of the Esc character.

UNIX Ports (WHICH, TEE, CUT) — Batch/Rexx/Perl/PowerShell/VBScript ports of essential Unix utilities. WHICH: locate executables in PATH (handles DOSKEY macros and CMD internals). TEE: split stdout to both screen and file simultaneously. CUT: extract columns/fields from text. Also includes TRUE/FALSE utilities for explicit errorlevel setting. Available as native batch (.bat), compiled Perl (.exe), and multiple scripting language versions.
Undocumented NT Commands — ACINIUPD (W2K Server): update INI files from command line (ACINIUPD /e "file.ini" "section" key "value"; /u for user directory; admin-only). SFC /SCANNOW: scan and replace corrupted protected system files. TSSHUTDN (Terminal Server): controlled server shutdown with user notification, reboot, and powerdown options.
DEBUG — 16-bit DOS debugger repurposed for batch scripting (32-bit OS only; unavailable on 64-bit). Read CMOS Real Time Clock (locale-independent date/time). Read VideoROM manufacturer info. Read I/O port addresses for COM/LPT ports. Check CapsLock/NumLock/ScrollLock status. Create tiny .COM utilities (e.g., REPLY.COM for user input, RESET.COM for reboot). Embed scripts in batch: DEBUG < %0.BAT / GOTO Around / script / :Around.
Clever Tips and Tricks — CMD /C quoting quirk: CMD /C @"command" "arg" (prefix @ to prevent misparse when first and last chars are quotes). Elevation check: WHOAMI /GROUPS | FIND "12288" (works in both 32-bit and 64-bit). PUSHD "%~dp0" auto-maps UNC paths to drive letters (works with RUNAS, PSEXEC, UAC). SET /P var=<file reads first line of file into variable. Large number math: FOR loop inserts spaces between digits for per-digit multiplication. FOR /F supports 31 tokens (not just 26) using escaped special characters like %%^^, %%_, %%\``. Swap mouse: RUNDLL32 USER32.DLL,SwapMouseButton. Resolve hostname: FOR /F “tokens=2” %%A IN (‘PING -a %1 ^| FIND “[%1]”’) DO ECHO %%A. Group commands for single redirect: (cmd1 & cmd2 & cmd3) > log.txt`.
ANSI Art and Console Colors — Use ANSI escape sequences to create colored text screens and animations. ANSI.SYS (DOS) or Windows 10 built-in support. FORFILES technique generates Esc characters on-the-fly. Alternatives: KOLOR.EXE (set color for text selection in 32/64-bit), BG by Carlos M. (modern BATCHMAN replacement), EKKO by Norman De Forest (ECHO enhancement with PROMPT-like color functions without ANSI driver).
AUTOEXEC.BAT — Automatic startup batch file executed by COMMAND.COM on boot (MS-DOS/Windows 9x). Used to set PATH, load TSRs, configure environment variables, and initialize devices. Not used in Windows NT+ (replaced by registry Run keys and startup folders).
PHP-Based Batch Files — Technique for mixing PHP code with batch files. PHP CLI processes the script while batch commands are hidden in PHP comments. Useful for leveraging PHP string functions, regex, and web capabilities from within a .bat wrapper.
Batch HowTos and Sample Collections — Curated collections of batch file techniques, how-to guides, and example scripts covering common Windows administration tasks. Topics include inventory scripts, login scripts, admin tools, network administration, and community-contributed solutions. “Poor Man’s Admin Tools” provides lightweight batch-only alternatives to commercial utilities (PMChoice, PMSleep, PMSoon, and others).
Useful NT Commands for Administrators — Reference of NT commands commonly used in administration batch scripts, including NET commands, SC (service control), TASKLIST/TASKKILL, WMIC, REG, SCHTASKS, ROBOCOPY, ICACLS, and system information utilities.

Batch Files And Functions

Batch Files, Scripts, and Functions

Utility Scripts

Batch Files And Functions

Batch Files, Scripts, and Functions

Utility Scripts

Date and Time

String and File Processing

File System

System and Configuration

Networking and Security

Miscellaneous

Best Practices and Debugging

Input Validation and Security

Variables and Data

String Processing

Math and Arithmetic

Devices and Hardware

Elevated Privileges

Files and Folders

Redirection and Encoding

Internet and Networking

Printing

Processes and Services

Program Flow

Registry

Date and Time

User Interaction

Miscellaneous and Collections