119
votes
6answers
14k views

How is PNG lossless given that it has a compression parameter?

PNG files are said to use lossless compression. However, whenever I am in an image editor, such as GIMP and try to save an image as a PNG file, it asks for the compression parameter, which ranges ...
119
votes
15answers
202k views

How can I send a Ctrl+Alt+Delete through Remote Desktop in Windows 8?

I need to send a CtrlAltDelete to a remote machine through Remote Desktop. The CtrlAltDelete is being intercepted by Windows 8, regardless of whether the remote desktop has focus or is in full screen. ...
119
votes
5answers
267k views

How can I display the contents of an environment variable from the command prompt in Windows 7?

In Windows 7, when I start the Command prompt, is there any command to display the contents of an environment variable (such as the JAVA_HOME or PATH variables)? I have tried with echo $PATH, echo ...
119
votes
14answers
92k views

Permanently remove/disable Touch Keyboard in Windows 8 taskbar?

I have Windows 8 (final, MSDN) on my Macbook Pro Retina. Windows 8's ongoing, continuous tantrum of insisting that it's on a tablet device is causing it to always have a touch keyboard 'icon' on the ...
118
votes
6answers
104k views

How can I delete a symbolic link?

I created a symlink using mklink. Now I need to change it but I can't figure out how to delete it so I can recreate it correctly.
117
votes
10answers
50k views

Get colors in 'less'' command

when I read a file in Linux with the command 'less' or 'more', how can I get the content in colors?
117
votes
5answers
113k views

How to list files of a Debian package without install

This command can only list contents of installed packages, dpkg -L PACKAGENAME but how to list contents of a non-installed package, to preview/examine the package?
114
votes
3answers
94k views

Go back to previous directory in shell

Is there a way to go back to previous directory we were in using bash,tcsh without using pushd/popd ? I'd like to type something like "back" and got returned to the previous directory I was in. Edit: ...
114
votes
5answers
10k views

How to identify whether my Linux computer was hacked?

My home PC is usually on, but the monitor is off. This evening I came home from work and found what looks like a hack attempt: in my browser, my Gmail was open (that was me), but it was in compose ...
113
votes
7answers
16k views

How to use the Internet while Heartbleed is being fixed?

There are many websites who are not currently vulnerable, but I have no idea if they were vulnerable a few days ago. For example: twitter.com: Not vulnerable right now, but the certificate is from ...
112
votes
4answers
115k views

How can I resume a stopped job in Linux?

How can I resume a stopped job in Linux? I was using emacs and accidentally hit ctrl-z which blasted me back to the console. I can see it when I type 'jobs' [*****]$ jobs [1]+ Stopped ...
112
votes
8answers
50k views

Find what package a file belongs to in Ubuntu/Debian?

I frequently find myself missing a program, man page, or other file when working on my Ubuntu 8.04 system. Is there any simple way to look up what package contains a given file (whether it is ...
112
votes
7answers
5k views

Why can't I email myself at: MyEmail@74.125.235.55?

I opened cmd and typed ping gmail.com. It shows me: C:\Windows\system32>ping gmail.com Pinging gmail.com [74.125.235.55] with 32 bytes of data: Reply from 74.125.235.55: bytes=32 time=6ms TTL=56 ...
112
votes
4answers
98k views

How to tell git which private key to use?

ssh has the -i option to tell which private key file to use when authenticating: -i identity_file Selects a file from which the identity (private key) for RSA or DSA authentication is read. ...
112
votes
5answers
297k views

What is the difference between an Intel i7 and a Xeon quad core processor?

I know the Xeon processors have been around for a long time and are mostly used in servers, but I am curious, why do people not use the Xeons in a high performance desktop? As far as I know about ...
111
votes
16answers
177k views

How to compare the differences between two PDF files on Windows?

Do you know a good Windows software to compare PDF files side-by-side and show the modifications between the two? It would be great if you can post both free and not-free products.
110
votes
8answers
8k views

What is the danger of inserting and browsing an untrusted USB drive?

Suppose someone wants me to copy some files to their USB stick. I'm running fully-patched Windows 7 x64 with AutoRun disabled (via Group Policy). I insert the USB drive, open it in Windows Explorer ...
110
votes
2answers
136k views

How to remove an entry from Chrome's Remembered URLs from the url bar?

I've got a URL in Chrome "local.mysite.com" that autopopulates when I start typing "local.my" into the URL bar. Note that this URL DOES NOT EXIST in my browser history (at ...
110
votes
7answers
118k views

Can I delete the the folder C:\ProgramData\Package Cache\?

There is a new folder full of installers located at C:\ProgramData\Package Cache\. I believe this is from visual studio 2012 RC. Does anyone know if I can delete these GB of data without ...
110
votes
4answers
166k views

Difference between OTF (Open Type) or TTF (True Type) font formats?

On a Mac, when I'm downloading fonts am often given the choice between OTF (OpenType Format) and TTF (TrueType Format). Is there any difference in the way ligatures work or anything between the two ...
110
votes
2answers
21k views

How to avoid exposing my MAC address when using IPv6?

On my Macs, each IPv6 address includes the MAC address of a specific computer (not of my router). Sites such as ipv6-test.com not only show it, but even tell me it belongs to an Apple computer. This ...
109
votes
5answers
23k views

Less and Grep: Getting colored results when using a pipe from grep to less

I use the --colour option of grep a lot, but I often use less as well. How can I pipe grep results to less and still preserve the coloring. (Or is that possible?) grep "search-string" -R * --colour | ...
109
votes
3answers
68k views

Is there anyway to stop Windows 8 from restarting for an update?

My Windows 8 machine is going to restart shortly... I have tried a few techniques such as shutdown /a which is not having much luck. Short of pausing the Windows Update service, is there anyway to ...
108
votes
8answers
122k views

Where does $PATH get set in OS X 10.6 Snow Leopard?

I type echo $PATH on the command line and get ...
108
votes
5answers
39k views

Scroll shell output with mouse in tmux

Mouse scrolling doesn't work in tmux the way it works when I run shell without tmux (in Gnome Terminal). It seems tmux sends mouse scroll events as if I pressed Up/Down keys. But I want it to scroll ...
108
votes
4answers
24k views

How does Windows know whether it has internet access or if a Wi-Fi connection requires in-browser authentication?

In Windows 7, the notification area networking icon will show an error indicator if there is no internet access , and the error icon goes away once there is a successful connection to the internet . ...
107
votes
5answers
251k views

How to mount a HFS partition in Ubuntu as Read/Write?

I plugged in my external harddrive (which was formatted on my Mac into HFS+ journaled) to my Ubuntu desktop 9.04 64bit. I am not able to get the drive to mount with write capability, how do I do ...
107
votes
6answers
103k views

chown is not changing symbolic link

I'm trying to change the user/group of a symbolic link with the command: $ chown -h myuser:mygroup mysymbolic/ But it's not changing. I'm logged in as root. The current user/group is set to ...
106
votes
19answers
18k views

How do I physically prevent people from unplugging an Ethernet cable?

We have a crowded computer laboratory. We render free Ethernet ports for laptop users. But they don't carry their Ethernet cables with them, they unplug cable of a fixed desktop PC and plug it to ...
106
votes
9answers
92k views

ssh tunnel via multiple hops

Tunneling data over ssh is pretty straight-forward: ssh -D9999 username@foreignhost.com sets up port 9999 on your localhost as a tunnel to foreignhost.com, but I have more specific need: I am ...
106
votes
8answers
41k views

Mac OS X equivalent of the Ubuntu “tree” command

Is there any equivalent of the Ubuntu tree command for Mac OS X ?
106
votes
5answers
110k views

How can I view two files side by side in Notepad++

I would like to split the Notepad++ window so that I can edit two files side by side. How can I do this in Notepad++?
106
votes
2answers
8k views

Why does Firefox use the “chrome://” protocol / schema in URLs? [duplicate]

When I want to configure an addon, for example Ghostery, the tab shows a URL like this one: chrome://ghostery/content/options.html What does it mean? Does it have something to do with the Chrome ...
106
votes
15answers
117k views

Looking for HTTP debugging proxy for Mac similar to Fiddler on Windows [closed]

In previous jobs when I've worked on a Windows machine, I've used Fiddler for viewing HTTP transactions and debugging. I'm specifically looking to monitor the HTTP transactions for an ajax site I'm ...
105
votes
18answers
9k views

What's the quickest way to count the number of each character in a file?

I want to count the A's T's C's G's N's and "-" characters in a file, or every letter if needed, is there a quick Unix command to do this?
105
votes
4answers
67k views

Way to avoid ssh connection timeout & freezing of terminal tab

When I connect via ssh terminal to certain servers, it timeouts and "freezes" the terminal (doesn't accept, doesn't disconnect, can't Ctrl-C to kill the ssh process or anything). This is in Ubuntu's ...
105
votes
7answers
83k views

Native alternative to wget in Windows PowerShell?

I know I can download and install the aformentioned library (wget for Windows), but my question is this: In Windows PowerShell, is there a native alternative to wget? I need wget simply to retrieve ...
104
votes
3answers
5k views

Is there a way to enable “god mode” in Windows 8, like you could in Windows 7?

I am looking for a way to enable God-Mode in Windows 8, does anyone know how to do this or is it even possible? It's a trick that lets you access all system's controls in one folder.
104
votes
10answers
61k views

How do I set up SSH so I don't have to type my password?

How do I set up SSH so I don't have to type my password when connecting to a host?
103
votes
9answers
81k views

How do I ensure Git doesn't ask me for my GitHub username and password?

I am working with a repo on GitHub and everytime I try to push something, it asks for my GitHub username and password. I don't want it doing that. I tried the instructions on setting your email in ...
103
votes
5answers
12k views

How should I choose my DNS?

When I have to choose my DNS I think that I should consider: Speed Reliability Privacy Control (reports and stats) The main options that come to my mind, and how I weigh them according to the ...
103
votes
4answers
11k views

What is the purpose of the tiny ruler that I've just pulled out of the side of my Dell Latitude E6430?

On the side of my Dell Latitude laptop, above the DVD drive, is a slot marked 'EC'. Pulling on it revealed a strangely shaped ruler with a temperature converter tool on the back. What is this? Why is ...
102
votes
7answers
38k views

How to tell from what Ubuntu or Debian repository a package comes?

On a Debian-based system, including Ubuntu, how can one tell which repository a package will be downloaded from, without actually beginning the download? aptitude show and apt-cache info will show the ...
102
votes
2answers
93k views

How to add user to a group from Mac OS X command line?

trying to add a user to a group from the command line but can't figure out how? Specifically this is on Mac OS X Server 10.5.8 like to add user to 'admin' and 'wheel' groups
102
votes
3answers
59k views

Where should the .vimrc file be located on Windows 7?

I recently installed vim on Windows 7 as a stand-alone binary. Where should I put my .vimrc file?
102
votes
7answers
60k views

How do you prevent the dock from switching monitors in OSX Mavericks?

In Mavericks, Apple introduced a "feature" where if you hover at the bottom of any screen the dock pops up on that screen. This is disrupting my workflow as I am constantly having the dock pop up ...
102
votes
6answers
42k views

Preventing applications from stealing focus

Are there any solutions to prevent applications stealing focus from the active window? This is especially annoying when I'm starting an application, switch to do something else and the new ...
101
votes
21answers
6k views

Easiest way to find out if user has either Windows 7 or Vista (through telephone support)?

If you have to provide some initial troubleshooting support by phone [or email], and you don't have access to the user's PC itself, what is the easiest and most foolproof question one can ask of the ...
101
votes
6answers
78k views

What's different between Ctrl+Z and Ctrl+C in Unix command line?

I'm using Mac OS X Terminal. And I use Ctrl+Z or Ctrl+C to stop some programs. But I realized that I don't know what they're exactly doing. What are they and what's the difference between them? ...
101
votes
12answers
191k views

How to force Internet Explorer (IE) to REALLY reload the page?

When using Internet Explorer 8 to test my web application I often find it doesn't reload the page, so I don't see my changes. This has resulted in a lot of wasted time and frustration wondering why my ...

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