I received a zip file containing data captured with
tcpdump on
a Linux system. When I tried to open the zip file on my
MacBook Pro
laptop running OS X El Capitan by double-clicking on the file within the
Finder,
I saw an "unable to expand" error message stating "Error 2 - No such file or
directory." A Microsoft Windows user who downloaded the same zip file reported
that he was unable to open it, either. When I tried to unzip the file from
a
Terminal window using the
unzip utility, I saw an "End-of-central directory signature not found" error
message.
$ file AS2_Captures.zip
AS2_Captures.zip: Zip archive data, at least v2.0 to extract
$ unzip AS2_Captures.zip
Archive: AS2_Captures.zip
End-of-central-directory signature not found. Either this file is not
a zipfile, or it constitutes one disk of a multi-part archive. In the
latter case the central directory and zipfile comment will be found on
the last disk(s) of this archive.
unzip: cannot find zipfile directory in one of AS2_Captures.zip or
AS2_Captures.zip.zip, and cannot find AS2_Captures.zip.ZIP, period.
$
Chromium is a
free and open-source (FOSS) web browser that is very
similar to the Google Chrome browser, though with
some differences. Google started the Chromium project as a means to
provide the source code for the proprietary Google Chrome browser. The
Chromium Project is headed by Google developers with input from community
developers.
If you wish to use the Chromium browser on a
CentOS
Linux system, you can install it by running the command
yum install chromium from the root account. You can check if
it is already installed on a CentOS system with rpm -qi chromium.
$ rpm -qi chromium
Name : chromium
Version : 60.0.3112.113
Release : 2.el7
Architecture: x86_64
Install Date: Tue 26 Sep 2017 10:35:46 AM EDT
Group : Unspecified
Size : 106438445
License : BSD and LGPLv2+ and ASL 2.0 and IJG and MIT and GPLv2+ and ISC and OpenSSL and (MPLv1.1 or GPLv2 or LGPLv2)
Signature : RSA/SHA256, Tue 29 Aug 2017 08:00:23 AM EDT, Key ID 6a2faea2352c64e5
Source RPM : chromium-60.0.3112.113-2.el7.src.rpm
Build Date : Mon 28 Aug 2017 08:21:06 PM EDT
Build Host : buildvm-22.phx2.fedoraproject.org
Relocations : (not relocatable)
Packager : Fedora Project
Vendor : Fedora Project
URL : http://www.chromium.org/Home
Summary : A WebKit (Blink) powered web browser
Description :
Chromium is an open-source web browser, powered by WebKit (Blink).
$
While checking the mail log file, /var/log/maillog, on an email
server today, I noticed an attempted login from an IP address in an address
range I didn't recognize. The entry in the log file contained the following
text:
dovecot: pop3-login: Disconnected (tried to use disallowed plaintext auth):
user=<>, rip=94.136.51.56
I checked the country associated with the 94.136.51.56 IP address
(ds7247.dedicated.turbodns.co.uk) with geoiplookup (you can install
the GeoIP package on a CentOS Linux system with yum install
GeoIP) and found it was an address assigned to an entity in
Great Britain.
$ geoiplookup 94.136.51.56
GeoIP Country Edition: GB, United Kingdom
$
If you see an error message like the one below, which was produced by Microsoft
Excel for Mac 2016 on a Mac OS X system, even though you don't have the file
open currently, then you will need to delete the lock file, which
should be in the same directory as the spreadsheet.
This file is locked for editing.
Locked by: John Doe
Filename: SGRS_2017.xlsm
You can open the file as read-only.
The lock file will have the same name as the workbook you were trying
to open, but the file name will have ~$ prepended to it. To
delete the file you will need to "escape" the meaning of the dollar sign
by putting an escape character, i.e., a backslash character, immediately
before the dollar sign. I.e., use ~\$ as shown below:
$ ls -alg **SGRS_2017.xlsm
-rw-rw-r--@ 1 ABC\Domain Users 761327 Sep 13 15:57 SGRS_2017.xlsm
-rw-rw-r--@ 1 ABC\Domain Users 171 Sep 18 22:46 ~$SGRS_2017.xlsm
$ rm ~$SGRS_2017.xlsm
rm: ~.xlsm: No such file or directory
$ rm ~\$SGRS_2017.xlsm
$
Once the lock file has been deleted, you should be able to open the
file without the warning message that it is locked for editing.
You can obtain the version of the
Microsoft Edge browser on a Windows system using the
Get-AppXPackage cmdlet with
Get-AppXPackage -Name Microsoft.MicrosoftEdge.
A user reported her Windows 10 Professional system was running slowly. On
September 14, 2017, I checked the system with
SUPERAntispyware, which reported
that it found the Ask Toolbar. It reported the following items associated with
the toolbar:
If you have a list in a
Python script and wish to add new items to the list, you can
use listname.append(newitem) where listname is
the name of the list and newitem is the item you wish to add to the list.
If you wish to add new items to the list only if they don't already
exist in the list, you can avoid adding an existing entry to the list
by checking if the entry is already in the list as shown below:
filenameList = []
if filename not in filenameList:
filenameList.append(filename)
If you wish to know the length of a list, i.e., how many items are
on the list, you can use print len(listname) where
listname is the name of your list.
You can backup a
table in a MySQL or MariaDB database by using the
mysqldump backup tool included with both database
management systems. To backup a specific table you can use the command
mysqldump database_nametable_name where
database_name is the name of the database that contains the table and
table_name is the name of the particular table you wish to backup. E.g.:
mysqldump -u ptolemy -p Planets Mars > Mars.sql
In the above case, if I have a database named Planets with
a table within it named Mars, I could backup just that one table
from the database with the command above. The -u option to the
command allows you to specify a MySQL/MariaDB username that has access to
the database and the -p option will prompt you for the password
associated with that username. The Mars.sql file will then
contain all of the
Structured Query
Language (SQL) commands needed to recreate the table structure and the
data in the table. E.g., it will contain insert SQL commands that will insert entries in the table.
I have a Python script,
filetype.py, that takes a file name as a parameter. I use the script
to identify if a file with a .bin extension is actually a
Microsoft Visio or
PowerPoint file. I run the script on an
OS X system
from a Terminal
window where I have a Bash shell prompt. E.g.:
$ ~/Documents/bin/filetype.py oleObject1.bin
Microsoft Office PowerPoint
$
But I often want to have it check all of the .bin files in a directory. You
can loop through all files in a directory or a set of files using a Bash
for loop.
E.g., to check all of the .bin files in a directory I could use the
for-loop below:
$ ls *
oleObject1.bin oleObject3.bin oleObject5.bin
oleObject2.bin oleObject4.bin oleObject6.bin
$ for f in *.bin; do ~/Documents/bin/filetype.py $f; done
Microsoft Office PowerPoint
Microsoft Office PowerPoint
Microsoft Office PowerPoint
Microsoft Visio
Microsoft Visio
oleObject6.bin: CDF V2 Document, No summary info
$
Someone who uses
GoDaddy for her email reported to me today that she couldn't
send email. I logged into her account from another system and was able to
send email to myself. When I notified her that I had been able to send email
from her acount to myself, she sent an email to me, but reported it was
still stating "loading" when she hit the send button. So tonight I logged into
her system and opened the Firefox browser, since she uses that browser to
send and receive email. When I clicked on Compose, I saw a "Loading..."
message in the body of the email that wouldn't go away unless I clicked on
the Plain Text tab to switch from "Rich Text", which allows one to
format text in the message with bolding, font colors, etc., to "Plain Text".
But when I switched back to "Rich Text", I had problems typing my email
address in the "To" field with only one letter appearing in the "To" field
no matter how many letters I typed.
If you need to know information about the manufacturer and model number of
a monitor on a Microsoft Windows system, you may be able to obtain it from
a PowerShell
prompt using the Get-WmiObject cmdlet as shown
below:
PS C:\> Get-WmiObject win32_desktopmonitor
DeviceID : DesktopMonitor1
DisplayType :
MonitorManufacturer : HP
Name : HP S2031 Series Wide LCD Monitor
ScreenHeight :
ScreenWidth :
PS C:\>
I manage a Linux server that functions as an email server using the
free and open source software (FOSS) package
sendmail.
I provide a mechanism through the server for someone who has
Verizon as his
Internet Service Provider (ISP) to send monthly newsletters
by email to an organization that has about thirteen hundred members on its
email distribution list, since he can't send to that number of people through
his ISP-provided email service. I do so by providing an
email alias
on my server, e.g., thelist@example.com that he puts in the
BCC line of his email. The alias is stored in /etc/aliases
and points to a text file containing the list of all members' email addresses.
So his ISP-provided
SMTP server sees only the one address, thelist@example.com,
which results in an email message to the server I manage that then translates
that address into the approximately 1,300 email addresses of members and sends
the newsletter to all members.
But this month the user reported he had sent the
message, but it had not been delivered to recipients. I first checked the
server's mail log, /var/log/maillog, for any occurrences of his
email address for the day he reported the problem. I use several free
DNS-based
Blackhole List (DNSBL) services to reduce the amount of
spam that
reaches user's inboxes, so I suspected that one of those services had blocked
email from the SMTP server through which he was sending his message, even
though I had whitelisted his email address quite some time ago by
adding a line like the following one to /etc/mail/access and
then running the command makemap hash /etc/mail/access
</etc/mail/access.
slartibartfast123987@verizon.net OK
I didn't find any references to his email address in the /var/log/mail
file, so I asked him to resend the message. I still didn't see any
references to his email address in the /var/log/maillog file,
but I did see that SORBS had blocked email from an
America Online (AOL)
server at the time he sent the message.
I wanted a simple easy to use application for managing my todo list that was
free and open source software (FOSS) which I could install
on Linux systems, but which might also be available for other operating systems
as well. There are online, commercial alternatives, but I wanted something
I could put on my own systems with no fear that my data might disappear should
a commercial entity not remain commercially viable. I found
Taskwarrior, an
open-source, cross platform time and task management tool with a
command-line interface (CLI). The command line interface is helpful to
me since I'm often working on systems via a Secure Shell (SSH) connection
and would like to be able to add to my task list on those systems without
using a graphical user
interface (GUI).
If you want to know what options you have for printing files on a Microsoft
Windows system, e.g., perhaps you want a list of currently avaialble printers
or even want to know the IP addresses by which some printers are accessible,
the
PowerShell Get-Printer cmdlet may provide the information you are seeking.
E.g.:
PS C:\Users\Pam> Get-Printer
Name ComputerName Type DriverName PortName Shared Published
---- ------------ ---- ---------- -------- ------ ---------
Microsoft XPS Document Writ... Local Remote Desktop Easy Print TS002 False False
Send To OneNote 2013 (redir... Local Remote Desktop Easy Print TS003 False False
Quicken PDF Printer (redire... Local Remote Desktop Easy Print TS001 False False
Send To OneNote 2010 Local Send To Microsoft OneN... nul: False False
Ricoh Aficio MP C2500 PCL5c Local Ricoh Aficio MP C2500 ... 192.168.0.90 True False
Microsoft XPS Document Writer Local Microsoft XPS Document... PORTPROMPT: False False
Microsoft Print to PDF Local Microsoft Print To PDF PORTPROMPT: False False
HP Deskjet 6940 series Local HP Deskjet 6940 series 192.168.0.9 True False
Fax Local Microsoft Shared Fax D... SHRFAX: False False
Adobe PDF Local Adobe PDF Converter Documents\*.pdf False False
ABS PDF Driver v400 Local Amyuni Document Conver... LPT1: False False
PS C:\Users\Pam>
