B

COMMAND-LINE UTILITIES

Table B.1 Windows 10’s Command-Line Disk Management Tools

Here’s the syntax for CHKDSK:

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CHKDSK [volume [filename]] [/F] [/V] [/R] [/B] [/X] [/I] [/C] [/L:[size]] [/scan]
  [/forceofflinefix] [/perf] [/spotfix] [/freeorphanedchains] [/markclean]
  [/offlinescanandfix] [/sdcleanup]

For example, to run a read-only check—that is, a check that doesn’t repair errors—on drive C, you enter the following command:

chkdsk c:

Note that when you use the /F switch to fix errors, CHKDSK must lock the volume to prevent running processes from using the volume during the check. If you use the /F switch on the %SystemDrive%, which is the drive where Windows 10 is installed (usually drive C:), CHKDSK can’t lock the drive, and you see the following message:

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Cannot lock current drive.
Chkdsk cannot run because the volume is in use by another
process. Would you like to schedule this volume to be
checked the next time the system restarts? (Y/N)

If you press Y and Enter, CHKDSK schedules a check for drive C: to run the next time you reboot Windows 10.

If you press Y and Enter at these prompts, CHKDSK adds the AUTOCHK utility to the following Registry setting:

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HKLMSYSTEMCurrentControlSetControlSession ManagerBootExecute

This setting specifies the programs that Windows 10 should run at boot time when the Session Manager is loading. AUTOCHK is the automatic version of CHKDSK that runs at system startup.

Windows 10 also comes with a command-line tool named CHKNTFS that enables you to cancel pending automatic disk checks, schedule boot-time disk checks without using CHKDSK, and set the time that AUTOCHK counts down before running the automatic disk checks.

Here’s the syntax for CHKNTFS:

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CHKNTFS [volume ][/C volume:] [/X volume:] [/D] [/T:[time]]

When you run CHKNTFS with just a volume name, you see one of the following:

If the volume is not scheduled for a startup disk check, you see the volume’s file system:

The type of the file system is NTFS.

If the volume is scheduled for a startup disk check, you see the following message:

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Chkdsk has been scheduled manually to run on next reboot.

If Windows 10’s Storage Manager has detected an error on the volume, it marks the volume as dirty, so in this case, you see the following message (using drive C: as an example):

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C: is dirty. You may use the /C option to schedule chkdsk for this drive.

This last message is confusing because Windows 10 always performs an automatic startup disk check of any volume that’s marked as dirty. What you can do with CHKNTFS is bypass the automatic startup disk check of any volume that is marked as dirty. To do that, run CHKNTFS with the /X switch, as in this example:

chkntfs /x c:

If a volume isn’t already marked as dirty, you can force CHKDSK to check a volume at startup by running CHKNTFS with the /C switch. For example, the following command sets up an automatic start check for the D: drive:

chkntfs /c d:

Note that the /C switch is cumulative, meaning that if you run it multiple times and specify a different volume each time, CHKNTFS adds each new volume to the list of volumes to check at startup. Instead of running multiple commands, however, you can specify multiple volumes in a single command, like so:

chkntfs /c c: d:

If you know a volume has been scheduled for a startup check but you want to cancel that check, run CHKNTFS with the /X switch, as in this example:

chkntfs /x d:

You can also specify multiple volumes if needed:

chkntfs /x c: d:

If you know that multiple volumes are scheduled for automatic startup checks, you can cancel all the checks by running CHKNTFS with the /D switch:

chkntfs /d

If you’ve scheduled a startup check for one or more volumes, or if a volume is marked as dirty, the next time you reboot Windows 10, you see a message similar to the following (which uses drive C: as an example):

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Checking file system on C:
The type of the file system is NTFS.
Volume label is SYS.

One of your disks needs to be checked for consistency. You
may cancel the disk check, but it is strongly recommended
that you continue.
To skip disk checking, press any key within 10 second(s).

The number of seconds in the last line counts down to 0. If you press a key before the countdown ends, Windows 10 skips the disk check; otherwise, it continues with CHKDSK.

You can change the initial countdown value by running CHKNTFS with the /T switch, followed by the number of seconds you want to use for the countdown. For example, the following command sets the countdown to 30 seconds:

chkntfs /t:30

Note that if you run the command CHKNTFS /T (that is, you don’t specify a countdown value), CHKNTFS returns the current countdown value.

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DEFRAG disks [task(s)] [/A] [/C] [/D] [/E] [/G] [/H] [/I n] [/K] [/L] [/M] [/O] [/T] [/U]
[/V] [/X]

For example, to get an analysis report of the fragmentation of drive C:, enter the following command:

defrag c: /a

If the volume isn’t too fragmented, you see a report similar to this:

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Post Defragmentation Report:
              Volume Information:
                Volume size               = 116.49 GB
                Free space                = 106.89 GB
                Total fragmented space    = 1%
                Largest free space size   = 56.49 GB
              Note: File fragments larger than 64MB are not
              included in the fragmentation statistics.
              You do not need to defragment this volume.

However, if the drive is quite fragmented, you see a report similar to the following:

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Post Defragmentation Report:
              Volume Information:
                Volume size                 = 397.12 GB
                Free space                  = 198.32 GB
                Total fragmented space      = 9%
                Largest free space size     = 158.43 GB
              Note: File fragments larger than 64MB are not
              included in the fragmentation statistics.

It is recommended that you defragment this volume.

If you try to defragment a volume that is running low on disk space, DEFRAG displays the following message:

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Volume DATA has only 9% free space available for use by Disk Defragmenter.
To run effectively, Disk Defragmenter requires at least 15% usable free space.
There is not enough disk space to properly complete the operation.
Delete some unneeded files on your hard disk, and then try again.

Table B.2 Windows 10’s Command-Line File and Folder Management Tools

The next few sections take a closer look at a half dozen of these tools: ATTRIB, FIND, REN, REPLACE, SORT, and XCOPY.

Before getting to the tools, we should mention that most of the file and folder management tools work with the standard wildcard characters: ? and *. In a file or folder specification, you use ? to substitute for a single character, and you use * to substitute for multiple characters. Here are some examples:

Archive—When this attribute is turned on, it means the file has been modified since it was last backed up.

Hidden—When this attribute is turned on, it means the file doesn’t show up in a DIR listing and isn’t included when you run most command-line tools. For example, if you run DEL *.* in a folder, Windows 10 deletes all the files in that folder, except the hidden files.

Integrity—When this attribute is set, it means the volume is configured with integrity, where data is stored in such a way that it is protected from certain types of file errors. Although technically available in Windows 10, this attribute works only with Windows 10 Server volumes formatted with the Resilient File System (ReFS) file system.

Offline—When this attribute is turned on, it indicates that the file is not currently available because its data has been moved to offline storage.

No scrub—When this attribute is set, the file is skipped by the scrubber, which is a background service that identifies and (if possible) fixes certain types of file errors. Again, this attribute works only with Windows 10 Server volumes formatted with the ReFS file system.

Not content indexed—When this attribute is set, the file’s contents will not be indexed for searching.

Read-only—When this attribute is turned on, it means the file can’t be modified or erased.

Pinned—When this attribute is set, it indicates the file is an NTFS sparse file. This tells Windows to allocate on disk only the file's nonzero (meaningful) data.

System—When this attribute is turned on, it means the file is an operating system file (that is, a file that was installed with Windows 10).

The ATTRIB command lets you turn these attributes on or off. Here’s the syntax:

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ATTRIB [+A | -A] [+H | -H] [+I | -I] [+O | -O] [+P | -P] [+R | -R] [+S | -S] [+U | -U] [+V | -V] [+X | -X]
filename [/S [/D] [/L]]

For example, if you want to hide all the .docx files in the current directory, use the following command:

attrib +h *.docx

As another example, if you’ve ever tried to delete or edit a file and received the message “Access denied,” the file is likely read-only. You can turn off the read-only attribute by running ATTRIB with the -R switch, as in this example:

attrib -r readonly.txt

You can also use ATTRIB for protecting important or sensitive files. When you hide a file, it doesn’t show up in a listing produced by the DIR command. Out of sight is out of mind, so someone taking a casual glance at your files won’t see the hidden ones and, therefore, won’t be tempted to display or erase them.

Although a hidden file is invisible, it’s not totally safe. Someone who knows the name of the file can attempt to modify the file by opening it with the appropriate program. As an added measure of safety, you can set the file’s read-only attribute. When you do this, the file can’t be modified. You can set both attributes by using a single command:

attrib +h +r payroll.xlsx

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FIND [/C] [/I] [/N] [/V] [/OFF[LINE]] "string" filename

For example, to find the string Xbox in a file named WishList.txt, you use the following command:

find "Xbox" WishList.txt

If the string you want to find contains double quotation marks, you need to place two quotation marks in the search string. For example, to find the phrase Dave “The Hammer” Schultz in the file players.doc, use the following command:

find "Dave ""The Hammer"" Schultz" players.doc

  FOR %f IN (filespec) DO FIND "string" %f

  FOR %f IN (*.doc) DO FIND "Thanksgiving" %f

  FOR %f IN (*.doc) DO FIND "Thanksgiving" "%f"

One of the most common uses of the FIND command is as a filter in pipe operations. In this case, instead of a filename, you pipe the output of another command through FIND. In this case, FIND searches this input for a specified string and, if it finds a match, displays the line that contains the string.

For example, the last line of a DIR listing tells you the number of bytes free on the current drive. Rather than wade through the entire DIR output just to get this information, use this command instead:

dir | find "free"

You’ll see something like the following:

2 Dir(s) 28,903,331,184 bytes free

FIND scours the DIR listing piped to it and looks for the word free. You can use this technique to display specific lines from, say, a CHKDSK report. For example, searching for bad finds the number of bad sectors on the disk.

REN old_filename new_filename

For example, the following command renames Budget 2017.xlsx to Budget 20187.xlsx:

ren "Budget 2017.xlsx" "Budget 2018.xlsx"

A simple file or folder rename such as this probably isn’t something you’ll ever fire up a command-line session to do because renaming a single object is faster and easier in File Explorer. However, the real power of the REN command is that it accepts wildcards in the file specifications. This enables you to rename several files at once—something you can’t do in File Explorer.

For example, suppose you have a folder full of files, many of which contain 2017 somewhere in the filename. To rename all those files by changing 2017 to 2018, you would use the following command:

ren *2017* *2018*

Similarly, if you have a folder full of files that use the .htm extension and you want to change each extension to .asp, you use the following command:

ren *.htm *.asp

Note that for these multiple-file renames to work, in most cases the original filename text and the new filename text must be the same length. For example, digital cameras often supply photos with names such as img_1234.jpg and img_5678.jpg. If you have a number of related photos in a folder, you might want to give them more meaningful names. If the photos are from a vacation in Rome, you might prefer names such as Rome_Vacation_1234.jpg and Rome_Vacation_5678.jpg. Unfortunately, the REN command can’t handle this type of change. However, it can rename the files to Rome_1234.jpg and Rome_5678.jpg:

ren img_* Rome*

The exception to the same-length rule is if the replacement occurs at the end of the filenames. For example, the following command renames all files with the .jpeg extension to .jpg:

ren *.jpeg *.jpg

It copies files, but only if their names match those in the target directory.

It copies files, but only if their names don’t exist in the target directory.

It copies files, but only if their names match those in the target directory and the matching files in the target directory are older than the files being copied.

Here’s the syntax:

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REPLACE source_files target /A /U /P /R /S /W

If you don’t specify switches, REPLACE copies a file from the source folder to the target folder if and only if it finds a file with a matching name in the target.

More useful is the REPLACE command’s updating mode, where it copies a file from the source folder to the target folder if and only if it finds a file with a matching name in the target and that target file is older than the source file. A good example where updating comes in handy is copying some files to a disk or memory card so that you can use them on another machine (such as taking files from your computer at work to use them at home). When you need to copy the files back to the first machine, the following REPLACE command does the job. (This assumes the disk or memory card is in the G: drive.)

replace g:*.* %UserProfile% /s /u

For each file on the G: drive, REPLACE looks for matching filenames anywhere in the %UserProfile% folder and its subfolders (thanks to the /S switch) and replaces only the ones that are newer (the /U switch).

What if you created some new files on the other computer? To copy those to the first machine, use the /A switch, as follows:

replace g:*.* %UserProfile%Documents /a

In this case, REPLACE copies a file from the G: drive only if it doesn’t exist in the %UserProfile%Documents folder. (You must specify a target folder because you can’t use the /S switch with /A.)

If the file is text, it’s often easier and faster to run the SORT command-line tool. By default, SORT takes the content of the file, sorts it in ascending alphanumeric order (0 to 9, then a to z, and then A to Z) starting at the beginning of each line in the file, and then displays the sorted results. You can also run descending order sorts, write the results to the same file or another file, and more. Here’s the syntax:

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SORT [input_file] [/+n] [/R] [/L locale] [/M kilobytes] [/REC characters]
[/T temp_folder] [/O output_file]

For example, the following SORT command sorts the data in records.txt and stores the results in sorted_records.txt:

sort records.txt sorted_records.txt

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XCOPY source destination [/A | /M] [/B] [/C] [/D[:mm-dd--yyyy]]
  [/EXCLUDE:file1[+file2[+file3]]] [/F] [/G] [/H] [/I] [/J] [/K] [/L] [/N]
  [/O] [/P] [/Q] [/R] [/S [/E]] [/T] [/U] [/V] [/W] [/X] [/Y | -Y] [/Z]

In its basic form, XCOPY works just like COPY. So, for example, to copy all the .doc files in the current folder to a folder called Documents in the G: drive, use the following command:

xcopy *.doc g:documents

Besides being faster, XCOPY also contains a number of features not found in the puny COPY command. Think of it as COPY on steroids. (The X in XCOPY means that it’s an extended COPY command.) For example, suppose you want to copy all the .doc files in the current folder and all the .doc files in any attached subfolders to G:Documents. With COPY, you first have to create the appropriate folders on the destination partition and then perform separate COPY commands for each folder, which is not very efficient, to say the least. With XCOPY, all you do is add a single switch:

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xcopy *.doc g:documents /s
xcopy *.bat d:atch /s

The /S switch tells XCOPY to copy the current folder and all nonempty subfolders, and to create the appropriate folders in the destination, as needed. (If you want XCOPY to copy empty subfolders, include the /E switch as well.)

Another useful feature of XCOPY is the ability to copy files by date. This is handy for performing incremental backups of files that you modified on or after a specific date. For example, suppose you keep your word processing documents in %UserProfile%Documents and you want to make backup copies in your Windows 10 user share of all the .doc files that have changed since August 23, 2016. You can do this by using the following command:

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xcopy %userprofile%documents*.doc \serverusers\%Username% /d:08-23-2016

It’s common to use XCOPY in batch files, but take care to handle errors. For example, what if a batch file tries to use XCOPY but there’s not enough memory? Or what if the user presses Ctrl+C during the copy? It might seem impossible to check for these kinds of errors; yet doing it is not only possible but also really quite straightforward.

When certain commands finish, they always file a report on the progress of the operation. This report, or exit code, is a number that specifies how the operation went. For example, Table B.3 lists the exit codes that the XCOPY command uses.

Table B.3 XCOPY Exit Codes

What does all this mean for your batch files? You can use a variation of the IF command—IF ERRORLEVEL—to test for these exit codes. For example, here’s a batch file that uses some of the XCOPY exit codes to check for errors:

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@ECHO OFF
XCOPY %1 %2
IF ERRORLEVEL 4 GOTO ERROR
IF ERRORLEVEL 2 GOTO CTRL+C
IF ERRORLEVEL 1 GOTO NO_FILES
GOTO DONE
:ERROR
ECHO Bad news! The copy failed because there wasn't
ECHO enough memory or disk space or because there was
ECHO something wrong with your file specs . . .
GOTO DONE
:CTRL+C
ECHO Hey, what gives? You pressed Ctrl+C to abort . . .
GOTO DONE
:NO_FILES
ECHO Bad news! No files were found to copy . . .
:DONE

As you can see, the ERRORLEVEL conditions check for the individual exit codes and then use GOTO to jump to the appropriate label.

One of the most important things to know about the IF ERRORLEVEL test is how Windows 10 interprets it. For example, consider the following IF command:

IF ERRORLEVEL 2 GOTO CTRL+C

Windows 10 interprets this command as “If the exit code from the last command is equal to or greater than 2, jump to the Ctrl+C label.” This has two important consequences for your batch files:

The test IF ERRORLEVEL 0 doesn’t tell you much because it’s always true. If you just want to find out whether the command failed, use the test IF NOT ERRORLEVEL 0.

To get the correct results, always test the highest ERRORLEVEL first and then work your way down.

Table B.4 Windows 10’s Command-Line System Management Tools

The next few sections take more detailed looks at five of these command-line tools: REG, SHUTDOWN, SYSTEMINFO, TYPEPERF, and WHOAMI.

REG actually consists of 11 subcommands, each of which enables you to perform different Registry tasks:

We won’t go through all these commands. Instead, we’ll focus on the three most common Registry tasks: viewing, adding, and changing Registry data.

To view the current value of the Registry setting, you use the REG QUERY command:

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REG QUERY KeyName [/V ValueName | /VE] [/C] [/D] [/E] [/F data] [/K | [/S]
  [/SE separator] [/T type] [/Z] [/reg:32 | /reg:64]

For example, if you want to know the current value of the RegisteredOwner setting in HKLMSoftwareMicrosoftWindows NTCurrentVersion, run the following command:

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reg query "hklmsoftwaremicrosoftwindows ntcurrentversion" registeredowner

The Registry Editor has a Find command that enables you to look for text within the Registry. However, it would occasionally be useful to see a list of the Registry keys and settings that contains a particular bit of text. You can do this by using the /F switch. For example, suppose you want to see a list of all the HKLM keys and settings that contain the text Windows Defender. Here’s a command that will do this:

reg query hklm /f "Windows Defender" /s

To add a key or setting to the Registry, use the REG ADD command:

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REG ADD KeyName [/V ValueName | /VE] [/D data] [/F | [/S separator] [/T type]  [/reg:32 | /reg:64]

For example, the following command adds a key named MySettings to the HKCU root key:

reg add hkcuMySettings

Here’s another example that adds a setting named CurrentProject to the new MySettings key and sets the value of the new setting to Win 8 In Depth:

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reg add hkcuMySettings /v CurrentProject /d "Win 8 In Depth"

If you want to make changes to an existing setting, run REG ADD on the setting. For example, to change the HKCUMySettingsCurrentProject setting to Windows 10 In Depth, you run the following command:

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reg add hkcuMySettings /v CurrentProject /d
"Windows 10 In Depth"

Windows 10 responds with the following prompt:

Value CurrentProject exists, overwrite (Yes/No)?

To change the existing value, press Y and press Enter.

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SHUTDOWN [[/R] | [/G] | [/S] | [/SG] | [/L] | [/H] | [/I] | [/P] | [/E] | [/A] |  [/O]] [/F |
   [/HYBRID] [/SOFT] [FW] [/D [P|U:]major:minor] [/M \ComputerName] [/T seconds] [/C "comment"]

For example, to restart your computer immediately, use the following command:

shutdown /r /t 0

If you’ve launched a restart or shutdown using some nonzero value for /T, and you need to cancel the pending shutdown, run SHUTDOWN with the /A switch before the timeout interval is over:

shutdown /a

The operating system name, version, manufacturer, and configuration type

The registered owner and organization

The original install date

The system boot time

The computer manufacturer, model, and system type

The system processors

The BIOS version

The total and available physical memory

The paging file’s maximum size, available size, in-use value, and location

The installed hotfixes

The network interface card data, such as the name, connection, DHCP status, and IP address (or addresses)

You can see all this data (and more), as well as control the output, by running SYSTEMINFO with the following syntax:

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SYSTEMINFO [/S computer] [/U [domain]username] [/P password]
  [/FO format] [/NH]

The output of SYSTEMINFO is quite long, so pipe it through the MORE command to see the output one screen at a time:

systeminfo | more

If you want to examine the output in another program or import the results into Excel or Access, redirect the output to a file and use the appropriate format. For example, Excel can read .csv files, so you can redirect the SYSTEMINFO output to a .csv file while using csv as the output format:

systeminfo /fo csv > systeminfo.csv

You can get the same benefit without the Performance Monitor GUI by using the powerful TYPEPERF command-line tool. Here’s the syntax:

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TYPEPERF [counter1 [counter2 ...]] [-CF file] [-O file] [-F format]
 [-SI interval] [-SC samples] [-Q [object]] [-QX [object]]
 [-CONFIG file] [-S computer] [-Y]

The official syntax of a counter path looks like this:

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[\Computer]Object([Parent/][Instance][#Index])Counter

In practice, however, you rarely use the Computer, Parent, and Index parts of the path, so most counter paths use one of the following two formats:

ObjectCounter
Object(Instance)Counter

For example, here’s the path for the Memory object’s Available MBytes counter:

MemoryAvailable MBytes

Here’s a TYPEPERF command that displays five samples of this counter:

typeperf "MemoryAvailable Mbytes" -sc 5

Similarly, here’s the path for the Processor object’s % Processor Time counter, using the first processor instance:

Processor(0)\% Processor Time

Here’s a TYPEPERF command that displays 10 samples of this counter every 3 seconds and saves the results to a file named ProcessorTime.txt:

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typeperf "Processor(0)\% Processor Time" -sc 10 -si 3 -o ProcessorTime.txt

To use the -CONFIG parameter with TYPEPERF, you must create a text file that stores the command-line parameters you want to use. This configuration file consists of a series of parameter/value pairs that use the following general format:

[Parameter]
Value

Here, Parameter is text that specifies a TYPEPERF parameter—such as F for the -F parameter and S for the -S parameter. Use C to specify one or more counter paths, and Value is the value you want to assign to the parameter.

For example, consider the following command:

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typeperf "PhysicalDisk(_Total)\% Idle Time" -si 5 -sc 10 -o idletime.txt

To run the same command using the -CONFIG parameter, you first need to create a file with the following text:

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[c]
PhysicalDisk(_Total)\% Idle Time
[si]
5
[sc]
10
[o]
idletime.txt

If this file is named IdleTimeCounter.txt, you can run it at any time with the following command (assuming IdleTimeCounter.txt resides in the current folder):

typeperf -config IdleTimeCounter.txt

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WHOAMI [/UPN | /FQDN | LOGONID] [/USER | /GROUPS | /CLAIMS | /PRIV] [/ALL]  [/FO format] [/NH]

You probably won’t use this command often on the Windows 10 computer because you’ll almost always be logged on as administrator. However, WHOAMI is useful when you’re working on a client computer and you’re not sure who is currently logged on.

For example, the following command redirects the current user’s SID, username, groups, and privileges to a file named whoami.txt using the list format:

whoami /all /fo list > whoami.txt

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NET USER [username [password | * | /RANDOM] [/ADD] [/DELETE] [options]]

Note, too, that if you execute NET USER without parameters, it displays a list of the local user accounts.

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NET LOCALGROUP [group name1 [name2 ...] {/ADD | /DELETE}

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NET USE [drive] [share] [password] [/USER:user]
 [/PERSISTENT:[YES | NO]] | /DELETE]

For example, the following command maps the shared folder \PAULSPCPaulWritingBooks to the Z: drive:

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net use z: \paulspcpaulwritingooks /persistent:yes

ARP—This utility displays (or modifies) the IP-to-Ethernet or IP-to-Token Ring address translation tables used by the Address Resolution Protocol (ARP) in TCP/IP. Enter the command arp -? for the syntax.

NBTSTAT—This utility displays the protocol statistics and the current TCP/IP connections using NBT (NetBIOS over TCP/IP). Enter nbtstat -? for the syntax.

NETSTAT—This utility displays the protocol statistics and current TCP/IP connections. Enter the command netstat -? to display the syntax.

NSLOOKUP—This utility queries the Domain Name System (DNS) that associates host and domain names with IP addresses, DNS servers, mail servers, and so on. Enter commands nslookup then help to display the syntax. (It's a complex tool; if we had room, we could devote an entire chapter to it.)

PING—This utility can check a network connection to a remote computer. This is one of the most commonly used TCP/IP diagnostic tools, so we describe it in more detail in Chapter 17, “Troubleshooting an Internet Connection.”

ROUTE—This utility can be used to manipulate a network routing table (LMHOSTS). Enter route -? for the syntax.

TRACERT—This utility can check the route taken to a remote host. We also explain this valuable diagnostic command in Chapter 17.

IPCONFIG—This utility displays the current TCP/IP network configuration. If you run the command ipconfig without switches, the utility returns your system’s current IP address, subnet mask, and default gateway. If you run the command ipconfig /all, the utility returns more detailed information.