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1500 questions
62
votes
8 answers
What are the advantages of tape drives?
IBM still develop and sell tape drives today. The capacity of them seems to be on a par with today's hard drives, but the search time and transfer rate are both significantly lower than that of hard drives.
So when is tape drives preferable to hard…
kba
- 2,947
62
votes
2 answers
ServerAliveCountMax in SSH
What does the ServerAliveCountMax in SSH actually do?
I am trying to ensure that when I connect to my server via SSH that the connection remains open for a long period of time instead of the connection dying after a short period of inactivity. This…
John Crawford
- 2,145
62
votes
12 answers
How do I make Linux recognize a new SATA /dev/sda drive I hot swapped in without rebooting?
Hot swapping out a failed SATA /dev/sda drive worked fine, but when I went to swap in a new drive, it wasn't recognized:
[root@fs-2 ~]# tail -18 /var/log/messages
May 5 16:54:35 fs-2 kernel: ata1: exception Emask 0x10 SAct 0x0 SErr 0x50000 action…
Philip Durbin
- 1,661
62
votes
7 answers
Where does UFW (uncomplicated firewall) save command-line rules to?
You add a rule like this:
ufw allow 22/tcp
The rule is saved, and is applied even after reboot. But it's not written anywhere in /etc/ufw. Where is it saved to? (Ubuntu, using ufw as pre-installed.)
Steve Bennett
- 6,000
62
votes
6 answers
Can an SSL certificate be on a single line in a file (no line breaks)?
SSL certificates by default have line breaks after 67 characters. I'm trying to create SSL certificate files using Chef. Essentially I want to create the entire certificate file from a string variable without any line breaks. I've tried this a few…
wrangler
- 3,300
62
votes
5 answers
How to configure vsftpd to work with passive mode
Whenever I install vsftpd on centos, I only setup the jail environment for the users and rest is default configuration of vsftpd. I create user and try to connect with filezila ftp client, but I could not connect with passive mode. I always change…
Toqeer
- 1,241
62
votes
5 answers
How can I hide the output of a shell application in Linux?
How can I hide the screen output (printf) of a shell application in Linux?
Jader Dias
- 4,785
62
votes
2 answers
When do DNS queries use TCP instead of UDP?
Possible Duplicate:
Is it true that a nameserver have to answer queries over TCP?
I know DNS uses UDP for most of its queries, but in what circumstances will it use TCP instead?
pradeepchhetri
- 3,018
62
votes
5 answers
Create Unix Named Socket from the Command Line
Is there a command similar to mkfifo but for domain sockets?
benmmurphy
- 865
- 1
- 8
- 8
62
votes
3 answers
Soft limit vs Hard limit?
Can anyone explain in layman's terms what the difference between soft and hard limit is?
Should I set my soft and hard limit to be the same? Or should soft be significantly lower? Does the system benefit either way?
kidcapital
- 877
62
votes
2 answers
How to run cron job on a specific hour every day?
What do I need to write in crontab to execute a script at 3pm every day?
john
- 1,025
62
votes
2 answers
What user do scripts in the cron folders run as? (i.e. cron.daily, cron.hourly, etc)
If I put a script in /etc/cron.daily on CentOS what user will it run as? Do they all run as root or as the owner?
Kyle MacFarlane
- 817
- 2
- 9
- 12
62
votes
18 answers
iptables Tips & Tricks
I'm sure Linux sysadmins are quite familiar with iptables, the userland interface to the netfilter packet-filtering framework.
Now, this "Question" is meant to be a Community Wiki for collecting together various bits-n-pieces of iptables wisdom.…
pepoluan
- 5,248
62
votes
10 answers
How to Chown a directory recursively including hidden files or directories
Seems like chown with the recursive flag will not work on hidden directories or files. Is there any simple workaround for that?
toby
- 721
62
votes
3 answers
Proxy HTTPS requests to a HTTP backend with NGINX
I have nginx configured to be my externally visible webserver which talks to a backend over HTTP.
The scenario I want to achieve is:
Client makes HTTP request to nginx which is redirect to the same URL but over HTTPS
nginx proxies request over…
Mike
- 955