I received an email message from someone that contained an attachment that had a .eml filename extension. When I viewed that file, I found the usual email header fields, i.e., "from", "to", "cc", and "subject", but for the body of the message I saw the following:

Content-Type: multipart/alternative;
        boundary="_000_22D42B1E120C59488B6A96BA13E639711E185536NDMSMBX403ndcna_"
MIME-Version: 1.0

--_000_22D42B1E120C59488B6A96BA13E639711E185536NDMSMBX403ndcna_
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64

QXMgZmFyIGFzIG15IGxpbWl0ZWQgdW5kZXJzdGFuZGluZyBvZiB0aGUgbWFpbCBzZXJ2ZXJzIGdv
<text snipped>
YnNwOzwvbzpwPjwvc3Bhbj48L3A+DQo8L2Rpdj4NCjxwIGNsYXNzPSJNc29Ob3JtYWwiPjxvOnA+
Jm5ic3A7PC9vOnA+PC9wPg0KPC9kaXY+DQo8L2JvZHk+DQo8L2h0bWw+DQo=

--_000_22D42B1E120C59488B6A96BA13E639711E185536NDMSMBX403ndcna_--

I needed to decode the base64 encoded text. Fortunately, Python has a base64 module that can be used for that purpose. So I created the following Python script to decode the encoded portion of the .eml file. The script expects the name of the input file to be provided on the command line and will print an error message and terminate if the file name isn't provided. If the filename is provided, the script will read the file line by line looking for the "Content-Transfer-Encoding: base64" which indicates that after one following blank line the encoded text will commence. The output will be displayed on the screen but can be redirected to a file.

#!/usr/bin/python

import base64, sys

try:
   sys.argv[1]
except IndexError:
   print "Error - missing input file name! Usage", sys.argv[0], "infile"
   sys.exit(1)
else:
   fileName = sys.argv[1]

base64_marker = "Content-Transfer-Encoding: base64"
block_of_lines = ""

with open(fileName) as input_data:
    # Skips text before the beginning of the base64 encoded block:
    for line in input_data:
        if line.strip() == 'Content-Transfer-Encoding: base64':
            break
    for line in input_data:  # Skip blank line
            break
    # Reads text until the end of the block:
    for line in input_data:  # Append lines to block_of_lines
        block_of_lines = block_of_lines + line
    print base64.b64decode(block_of_lines)

[/languages/python] permanent link

You can use wmic os get commands on a Microsoft Windows system to view information related to the operating system via a command-line interface (CLI). E.g., to determine the version of the operating system you can issue the command Windows Management Instrumentation Command-line (WMIC) command wmic os get version.

C:\Users\Public>wmic os get version
Version
10.0.15063


C:\Users\Public>

Or if you know the system is running a particular version of the Windows operating system, e.g., Windows 10, but want to see just the build number for that version of Windows, you could issue the command wmic os get BuildNumber.

C:\Users\Public>wmic os get BuildNumber
BuildNumber
15063


C:\Users\Public>

[ More Info ]

[/os/windows/commands/wmic] permanent link

To view the list of documents contained in a PDF document with Adobe Acrobat Reader DC on a Mac OS X system, with the file open in Acrobat Reader DC, click on File then select Properties and then click on the Fonts tab.

[ More Info ]

[/os/os-x] permanent link

A user reported that when she printed Microsoft Excel spreadsheets or QuickBooks invoices, no text would appear on the printouts. She had reported the same problem about a month ago. When I rebooted the system then, the problem went away, but this time rebooting didn't help. After I requested that she reboot the system, I was told the problem remained, so when I was able to get to the system to troubleshoot, I first checked to make sure the system had been rebooted rather than QuickBooks simply being restarted. It was then that I noticed a lot of other functionality was no longer available. E.g., when I tried to use the systeminfo command to find the last reboot time, I saw an error message instead of the time the system was last rebooted.

Microsoft Windows [Version 10.0.15063]
(c) 2017 Microsoft Corporation. All rights reserved.

C:\Users\Pam>systeminfo | find /i "Boot"
Loading Operating System Information ...ERROR: Invalid class

C:\Users\Pam>systeminfo
Loading Operating System Information ...ERROR: Invalid class

C:\Users\Pam>wmic os get lastbootuptime
os - Alias not found.

C:\Users\Pam>

[ More Info ]

[/os/windows/win10] permanent link

You can determine the version of Microsoft Windows installed on a system from a PowerShell prompt using [System.Environment]::OSVersion.Version or (Get-WmiObject -class Win32_OperatingSystem).Caption.

PS C:\Users\Public> [System.Environment]::OSVersion.Version

Major  Minor  Build  Revision
-----  -----  -----  --------
10     0      15063  0


PS C:\Users\Public> (Get-WmiObject -class Win32_OperatingSystem).Caption
Microsoft Windows 10 Pro
PS C:\Users\Public> (Get-WmiObject -class Win32_OperatingSystem)


SystemDirectory : C:\WINDOWS\system32
Organization    : Microsoft
BuildNumber     : 15063
RegisteredUser  : Jeanne
SerialNumber    : 00330-80000-00000-AA775
Version         : 10.0.15063



PS C:\Users\Public>

[ More Info ]

[/os/windows/PowerShell] permanent link

You can use the PowerShell Get-Disk cmdlet to query disk drives within or attached to a PC running the Microsoft Windows operating system. E.g.:

PS C:\Users\Public> Get-Disk

Number Friendly Name Serial Number                    HealthStatus         OperationalStatus      Total Size Partition
                                                                                                             Style
------ ------------- -------------                    ------------         -----------------      ---------- ----------
0      ST3320418AS               9VMNNJDN             Healthy              Online                  298.09 GB MBR
4      Generic- C... 058F63626421                     Healthy              No Media                      0 B RAW
6      Generic- M... 058F63626423                     Healthy              No Media                      0 B RAW
3      Generic- S... 058F63626420                     Healthy              No Media                      0 B RAW
5      Generic- S... 058F63626422                     Healthy              No Media                      0 B RAW
1      Lexar USB ... AA58ZF9FJCCALAOA                 Healthy              Online                   14.92 GB MBR
2      WD My Pass... WXP1A27034VH                     Healthy              Online                  931.48 GB GPT


PS C:\Users\Public>

[ More Info ]

[/os/windows/PowerShell] permanent link

I had created the following function to establish the connection to the SQLITE 3 database:

def create_connection (db_file):
   """ Create a database connection to an SQL database
       Return connection object or none """
   try:
      conn = sqlite3.connect(db_file)
      return conn
   except Exception as e:
      print(e)
   return None

[ More Info ]

[/languages/python] permanent link

If you want to determine how long a Microsoft system has been running since it was last rebooted from a command-line interface (CLI), you can do so using PowerShell. You can do so by subtracting the last boot time from the current date and time. The Get-Date cmdlet shows the current date and time and (Get-CimInstance Win32_OperatingSystem).LastBootUpTime shows the last time the system was booted.

PS C:\Users\public\documents> (Get-CimInstance Win32_OperatingSystem).LastBootUpTime

Tuesday, October 10, 2017 9:12:14 PM


PS C:\Users\public\documents> (Get-Date) - (Get-CimInstance Win32_OperatingSystem).LastBootUpTime


Days              : 3
Hours             : 1
Minutes           : 29
Seconds           : 26
Milliseconds      : 717
Ticks             : 2645667172021
TotalDays         : 3.06211478243171
TotalHours        : 73.4907547783611
TotalMinutes      : 4409.44528670167
TotalSeconds      : 264566.7172021
TotalMilliseconds : 264566717.2021



PS C:\Users\public\documents>

You can use the alias GCIM for Get-CimInstance to save some typing, if you wish.

PS C:\Users\public\documents> (GCIM Win32_OperatingSystem).LastBootUpTime

Tuesday, October 10, 2017 9:12:14 PM


PS C:\Users\public\documents>

[/os/windows/PowerShell] permanent link

After I rebooted a Windows 10 PC subsequent to a software update on the system, when I attempted to reopen Microsoft Outlook 2016, I saw the message below:

Outlook Data File

---

The file C:\Users\jasmith1\AppData\Local\Microsoft\Outlook\john.a.smith@exmple.com.ost is in use and cannot be accessed. Close any application that is using this file, and then try again. You might need to restart your computer.

OK

[ More Info ]

[/network/email/clients/outlook/2016] permanent link

If you are accustomed to using the wget or cURL utilities on Linux or Mac OS X to download webpages from a command-line interface (CLI), there is a Gnu utility, Wget for Windows , that you can download and use on systems running Microsoft Windows. Alternatively, you can use the Invoke-WebRequest cmdlet from a PowerShell prompt, if you have version 3.0 or greater of PowerShell on the system. You can determine the version of PowerShell on a system by opening a PowerShell window and typing $psversiontable. E.g., in the example below from a Windows 10 system, the version of PowerShell is 5.1.15063.674.

PS C:\Users\public\documents> $psversiontable

Name                           Value
----                           -----
PSVersion                      5.1.15063.674
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.15063.674
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1


PS C:\Users\public\documents>

If you have version 3.0 or later, you can use wget or curl as an alias for the Invoke-WebRequest cmdlet, at least up through version 5.x. E.g., if I want to download the home page for the website example.com to a file named index.html, I could use the command wget -OutFile index.html http://example.com at a PowerShell prompt. Or I could use either of the following commands, instead:

curl -OutFile index.html http://example.com
Invoke-WebRequest -OutFile index.html http://example.com

[ More Info ]

[/os/windows/PowerShell] permanent link

You can check version information for a Dynamic-link Library (DLL) file, i.e., a file with a .dll filename extension, or a executable file, i.e., a .exe file, from a command-line interface (CLI) on a Microsoft Windows system by using the Get-Item cmdlet. E.g.:

PS C:\> (Get-Item C:\Windows\explorer.exe).VersionInfo

ProductVersion   FileVersion      FileName
--------------   -----------      --------
10.0.15063.0     10.0.15063.0 ... C:\Windows\explorer.exe


PS C:\>

If you can't see all of the information, i.e., if you see three dots indicating that not all of the information is displayed, you can append | format-list to the command to have the output displayed in list format.

PS C:\> (Get-Item C:\Windows\explorer.exe).VersionInfo | format-list


OriginalFilename  : EXPLORER.EXE.MUI
FileDescription   : Windows Explorer
ProductName       : Microsoft® Windows® Operating System
Comments          :
CompanyName       : Microsoft Corporation
FileName          : C:\Windows\explorer.exe
FileVersion       : 10.0.15063.0 (WinBuild.160101.0800)
ProductVersion    : 10.0.15063.0
IsDebug           : False
IsPatched         : False
IsPreRelease      : False
IsPrivateBuild    : False
IsSpecialBuild    : False
Language          : English (United States)
LegalCopyright    : © Microsoft Corporation. All rights reserved.
LegalTrademarks   :
PrivateBuild      :
SpecialBuild      :
FileVersionRaw    : 10.0.15063.608
ProductVersionRaw : 10.0.15063.608



PS C:\>

[ More Info ]

[/os/windows/PowerShell] permanent link

[ More Info ]

[/os/os-x] permanent link

I sometimes need to determine the day of the year corresponding to today's date. The day of year starts with January 1 as day 1 and for 2017, December 31 is day 365. You can find sites online that will provide those values, e.g. Day Numbers for 2017 or NOAA's DOY Calendar. Or, on a system with Python installed, e.g., Linux or OS X, you can use the datetime module to obtain the day of the year corresponding to the current date as shown below:

$ python
Python 2.7.10 (default, Oct 23 2015, 19:19:21) 
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.59.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import datetime
>>> datetime.datetime.today().timetuple().tm_yday
280
>>> exit()
$

Since today is October 7 of the year 2017, the day of the year is 280.

If you want to obtain the day of year (DOY) for another date, you can use datetime.date(year, month, day).timetuple().tm_yday where year is the relevant year, month is the month, and day is the day of interest. E.g., March 1, 2017 is DOY 60:

>>> import datetime
>>> datetime.date(2017, 3, 1).timetuple().tm_yday
60
>>>

[/languages/python] permanent link

If you want to determine the IP address of the DHCP server from which a Mac OS X system received its IP address, subnet mask, etc., you can obtain that information from a command-line interface (CLI), i.e., a Terminal window by using the command ipconfig getpacket interface where interface is the relevant network interface, which will usually be en0 or en1. You can issue the command ifconfig -a in a Terminal window to see the network interfaces on the system and which have IP addresses assigned to them.

[ More Info ]

[/os/os-x] permanent link

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[/languages/python] permanent link