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1500 questions
596
votes
15 answers

When reading a file with `less` or `more`, how can I get the content in colors?

When I read a file in Linux with the command less or more, how can I get the content in colors?
Open the way
  • 8,613
593
votes
9 answers

Using ffmpeg to cut up video

I am using ffmpeg to cut out a section of a large file like this: ffmpeg -i input.wmv -ss 60 -t 60 -acodec copy -vcodec copy output.wmv The -ss part works fine but the -t is ignored. It correctly removes the initial specified seconds specified with…
Neil
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585
votes
12 answers

Automatically answer 'Yes' when using apt-get install

Is there a way to make apt-get install automatically choose "yes" upon the Do you want to continue [y/N]? confirmation dialog?
mistiry
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576
votes
7 answers

What is the "You have new mail" message in Linux/UNIX?

Sometimes, when I log into a box and 'su' to root, I get a cute little message saying I have mail (thank GOD it's not AOL). Where is this mail? What does it contain? Who/What sent it? How important is it? Is this even actual "mail" in the same…
nopcorn
  • 16,662
570
votes
4 answers

How to turn off word-wrap in less

Short version: How can I make the less utility in Linux not wrap lines? Long version: Often I need to view huge CSV files using less with hundreds of columns. I frequently only care about the first couple columns. However, word wrap causes one…
User1
  • 9,342
565
votes
3 answers

"directory junction" vs "directory symbolic link"?

In the context of NTFS: MKLINK [[/D] | [/H] | [/J]] Link Target /D Creates a directory symbolic link. Default is a file symbolic link. /H Creates a hard link instead of a symbolic link. /J Creates a Directory Junction. Link …
Pacerier
  • 27,223
565
votes
16 answers

Reload a Linux user's group assignments without logging out

When assigning a user's secondary group list using: # usermod -G is it possible to force this group assignment to take effect without logging out all running sessions? This would be very useful in the situation where a Screen…
Simon
  • 6,142
565
votes
6 answers

Difference between .bashrc and .bash_profile

What's the difference between .bashrc and .bash_profile and which one should I use?
cfischer
  • 9,063
564
votes
12 answers

Can I make cURL fail with an exitCode different than 0 if the HTTP status code is not 200?

I was always assuming that when curl got an HTTP 500 response it was returning an exit code that meant failure (!= 0), but that seems to be not the case. Is there a way I can I make cURL fail with an exitCode different than 0 if the HTTP status code…
knocte
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562
votes
13 answers

Windows 7 SP1 Windows Update stuck checking for updates

I installed Windows 7 fresh and installed SP1. Now, when I try to check manually for Windows Updates it just hangs on the Checking for updates screen. I tried running the tools in How do I reset Windows Update components?, but this did not fix the…
549
votes
5 answers

How do I run multiple commands on one line in PowerShell?

In a cmd prompt, you can run two commands on one line like so: ipconfig /release & ipconfig /renew When I run this command in PowerShell, I get: Ampersand not allowed. The `&` operator is reserved for future use Does PowerShell have an operator…
David
  • 9,334
544
votes
14 answers

How do I make rm not give an error if a file doesn't exist?

I'm writing a makefile that will clean up some useless files at the end of the compilation. If a target has already been made, it will of course skip that target and the useless file may not be there. So if I do this: rm lexer.ml interpparse.ml…
Jason Baker
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534
votes
6 answers

Remove audio from video file with FFmpeg

How can I strip the audio track out of a video file with FFmpeg?
TeAmEr
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528
votes
6 answers

How to decompress a .bz2 file

I have a file as: filename.bz2 I need to decompress. I have tried the command: tar xvjf filename.tar.bz2, but it didn't work as the file is not a tar file. How do I decompress this file?
Jury A
  • 5,425
520
votes
15 answers

How to fix warning about ECDSA host key

I'm trying to setup password-less SSH on an Ubuntu server with ssh-copy-id myuser@myserver, but I'm getting the error: Warning: the ECDSA host key for 'myserver' differs from the key for the IP address '192.168.1.123' What's causing this, and how…
Cerin
  • 9,142