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1500 questions
128
votes
4 answers
Amazon EC2 terminology - AMI vs. EBS vs. Snapshot vs. Volume
I have been poking around Amazon EC2, and am a little confused on some of the terminology. Specifically with regard to AMI, snapshots and volumes, and an EBS
Please correct me if I am wrong, or fill in any serious gaps in my following…
Matt
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128
votes
2 answers
Colors in bash after piping through less?
When I have dircolors defined life is full of... color.
When I pipe ls through less to scroll around I lose the colors.
Any suggestions?
MathewC
- 6,957
- 9
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128
votes
17 answers
Switching to IPv6 implies dropping NAT. Is that a good thing?
This is a Canonical Question about IPv6 and NAT
Related:
How does IPv6 subnetting work and how does it differ from IPv4 subnetting?
How can I 'dip my toes' into dynamic IPv6 network addressing?
IPv6 without nat but what about an isp change?
Our…
Ernie
- 5,352
- 6
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128
votes
13 answers
How to tell if a Linux system is big endian or little endian?
I know that certain processors are Big Endian and others are Little Endian. But is there a command, bash script, python script or series of commands that can be used at the command line to determine if a system is Big Endian or Little Endian?…
Jake Wilson
- 8,814
- 29
- 97
- 125
127
votes
10 answers
Can you run Docker natively on the new Windows 10 (Ubuntu) bash userspace?
My understanding was that the primary limitation of running docker on other OSs was the Linux Network containers that made it possible. (Certainly for Macs).
Recently Microsoft announced a beta of a Ubuntu linux user mode running natively on…
Hawkeye
- 2,699
- 9
- 30
- 35
127
votes
15 answers
Mount CIFS Host is down
I have an issue with a mount point that was previously configured. It shows the folder, but the mount is missing and holds "?" values for size, permissions, etc.
So I tried to remount using cifs and the same command from before:
mount -t cifs…
Kevin
- 1,403
- 2
- 11
- 9
127
votes
4 answers
Postgresql: what does GRANT ALL PRIVILEGES ON DATABASE do?
I'm trying to grant all privileges on all tables of a given database to a new postgres user (not the owner). It seems that GRANT ALL PRIVILEGES ON DATABASE my_db TO new_user; does not do that. After running said command successfully (as the…
rz.
- 1,373
- 2
- 9
- 7
127
votes
4 answers
How can I see Time-To-Live (TTL) for a DNS record?
I would like to see the Time-To-Live (TTL) value for a CNAME record.
I have access to dig (on Apple Mac OS X), which gives me an answer like this:
% dig host.example.gov
<*SNIP*>
;; ANSWER SECTION:
host.example.gov. 43200 IN CNAME …
Stefan Lasiewski
- 23,667
- 41
- 132
- 186
126
votes
6 answers
Postfix - how to retry delivery of mail in queue?
I have a backup mail server in case of a failure on the main one.
In that case of failure, mails come on the backup server and stay there until the main one is back.
If I wait some times, the delivery will be done automatically as soon as the main…
Nicolas
- 1,269
- 2
- 8
- 3
125
votes
11 answers
Prevent duplicate cron jobs running
I have scheduled a cron job to run every minute but sometimes the script takes more than a minute to finish and I don't want the jobs to start "stacking up" over each other. I guess this is a concurrency problem - i.e. the script execution needs to…
Tom
- 4,277
- 11
- 42
- 52
125
votes
4 answers
Nginx: How do I forward an HTTP request to another port?
What I want to do is: When someone visits http://localhost/route/abc the server responds exactly the same as http://localhost:9000/abc
Now I configure my Nginx server like this:
location /route {
proxy_pass http://127.0.0.1:9000;
}
The HTTP…
WoooHaaaa
- 1,605
- 4
- 15
- 13
125
votes
5 answers
How do you do load testing and capacity planning for web sites?
This is a canonical question about capacity planning for web sites.
Related:
Can you help me with my capacity planning?
How do you do load testing and capacity planning for databases?
What are some recommended tools and methods of capacity…
gWaldo
- 11,957
- 8
- 42
- 69
125
votes
4 answers
How to check if a port is blocked on a Windows machine?
On the Windows platform, what native options to I have to check if a port (3306, for example) on my local machine (as in localhost), is being blocked?
Boris Pavlović
- 1,363
- 2
- 9
- 8
124
votes
3 answers
How can I rename a Unix user?
I have a user named hedgehog and I want him to be named squirrel, but I don't want to change his numeric user ID.
How can I accomplish this?
Szymon Jeż
- 3,377
- 3
- 17
- 17
124
votes
7 answers
How does CTRL-ALT-DEL to log in make Windows more secure?
When logging into Windows, it says on that page that CTRL-ALT-DEL somehow makes Windows more secure. I have never been able to figure a mechanism where having to press some specific key combination before logging in makes the system more secure. I…
Eddie
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- 37
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