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1500 questions
737
votes
4 answers
Difference between nohup, disown and &
What are the differences between
$ nohup foo
and
$ foo &
and
$ foo &
$ disown
Lesmana
- 25,703
- 20
- 76
- 82
734
votes
4 answers
How to cycle through reverse-i-search in BASH?
In the terminal, I can type Ctrl + R to search for a matching command previously typed in BASH. E.g., if I type Ctrl + R then grep, it lists my last grep command, and I can hit enter to use it. This only gives one suggestion though. Is there any way…
Village
- 5,299
- 14
- 45
- 75
734
votes
5 answers
What does "--" (double-dash) mean?
I have seen -- used in the compgen command.
For example:
compgen -W "foo bar baz" -- b
What is the meaning of the -- in there?
dogbane
- 27,629
- 13
- 78
- 60
717
votes
12 answers
How can I reduce a video's size with ffmpeg?
How can I use ffmpeg to reduce the size of a video by lowering the quality (as minimally as possible, naturally, because I need it to run on a mobile device that doesn't have much available space)?
I forgot to mention that when the video can use…
xralf
- 15,197
- 27
- 97
- 142
687
votes
10 answers
How to switch between users on one terminal?
I'd like to log in as a different user without logging out of the current one (on the same terminal). How do I do that?
tshepang
- 61,932
- 85
- 220
- 285
686
votes
8 answers
What do the numbers in a man page mean?
So, for example, when I type man ls I see LS(1). But if I type man apachectl I see APACHECTL(8) and if I type man cd I end up with cd(n).
I'm wondering what the significance of the numbers in the parentheses are, if they have any.
Wilduck
- 6,987
- 3
- 14
- 6
680
votes
24 answers
Preserve bash history in multiple terminal windows
I consistently have more than one terminal open. Anywhere from two to ten, doing various bits and bobs. Now let's say I restart and open up another set of terminals. Some remember certain things, some forget.
I want a history that:
Remembers…
Oli
- 15,218
- 7
- 41
- 51
675
votes
5 answers
Zip all files in directory?
Is there a way to zip all files in a given directory with the zip command? I've heard of using *.*, but I want it to work for extensionless files, too.
tkbx
- 9,867
- 12
- 34
- 41
668
votes
4 answers
Why is printf better than echo?
I have heard that printf is better than echo. I can recall only one instance from my experience where I had to use printf because echo didn't work for feeding some text into some program on RHEL 5.8 but printf did. But apparently, there are other…
amphibient
- 11,842
- 18
- 60
- 85
668
votes
29 answers
Why am I still getting a password prompt with ssh with public key authentication?
I'm working from the URL I found here:
http://web.archive.org/web/20160404025901/http://jaybyjayfresh.com/2009/02/04/logging-in-without-a-password-certificates-ssh/
My ssh client is Ubuntu 64 bit 11.10 desktop and my server is Centos 6.2 64 bit. I…
Thom
- 7,245
- 4
- 17
- 16
663
votes
9 answers
How do I zip/unzip on the unix command line?
How can I create and extract zip archives from the command line?
joachim
- 7,427
- 4
- 16
- 8
639
votes
5 answers
/usr/bin vs /usr/local/bin on Linux
Why are there so many places to put a binary in Linux? There are at least these five:
/bin/
/sbin/
/usr/bin/
/usr/local/bin/
/usr/local/sbin/
And on my office box, I do not have write permissions to some of these.
What type of binary goes into…
Lazer
- 33,497
- 24
- 68
- 74
633
votes
3 answers
Using "${a:-b}" for variable assignment in scripts
I have been looking at a few scripts other people wrote (specifically Red Hat), and a lot of their variables are assigned using the following notation
VARIABLE1="${VARIABLE1:-some_val}"
or some expand other variables
VARIABLE2="${VARIABLE2:-`echo…
Justin Garrison
- 7,207
- 3
- 19
- 21
628
votes
10 answers
Why is it better to use "#!/usr/bin/env NAME" instead of "#!/path/to/NAME" as my shebang?
I notice that some scripts which I have acquired from others have the shebang #!/path/to/NAME while others (using the same tool, NAME) have the shebang #!/usr/bin/env NAME.
Both seem to work properly. In tutorials (on Python, for example), there…
TheGeeko61
- 6,651
- 3
- 16
- 17
625
votes
19 answers
How to get execution time of a script effectively?
I would like to display the completion time of a script.
What I currently do is -
#!/bin/bash
date ## echo the date at start
# the script contents
date ## echo the date at end
This just show's the time of start and end of the script. Would it be…
mtk
- 25,150
- 34
- 89
- 125