FreeBSD command reference. Command structure. Each line you type at the Unix shell consists of a command optionally followed by some arguments, e.g. Updated: 12/29/ by Computer Hope. telnet command. About telnet; telnet syntax; telnet examples; Related commands; Linux and Unix commands help. This document is a collection of Unix/Linux/BSD commands and tasks which are useful for IT work or for advanced users. This is a practical guide with concise.
Some rights reserved under Creative Commons. Basics Script example awk sed Regular Expressions useful commands. Unix Toolbox revision On a duplex printer the booklet will create a small book ready to bind. See also the about page. Error reports and comments are most welcome – c cb.
To temporarily prevent logins system wide for all users but root use nologin. The message in nologin will be displayed might not work with ssh pre-shared keys. The default limits are usually too low. The status is checked with ulimit ubix. For example to change the open files limit from to do: An unlimited value is still limited by the system maximal value.
System wide Kernel limits are also set with sysctl. The syntax is the same as Linux but the keys are different. And also FreeBSD performance tuning http: It is usually 3 kmendy 5: The actual runlevel can be changed with init.
Komendy Unix –
For example to go from 3 to 5: Default is to start in 2,3,4 and 5 and shutdown in 0,1 and 6. With explicit arguments update-rc.
The scripts responds at least to start stop status. For example init 6 for reboot. Reset root password Linux method 1 At the boot loader lilo or grubenter the following boot option: Use the command passwd at the prompt to change the password and then reboot. Forget the single user mode as you need the password for that. If, after booting, the root partition is mounted read only, remount it rw: You can select the single user mode on the boot menu option 4 which unis displayed for 10 seconds at startup.
The solution is to mount the root partition from an other OS like a rescue CD and change the password on the disk. Boot a live CD or installation CD into a rescue mode which will give you a shell. Find the root partition with fdisk e. Faster system, but a little risky. A list of all running process is retrieved with ps. Negative numbers have a higher prioritythe lowest is and “nice” have a positive value.
Positive is “nice” or weak, negative is strong scheduling priority. This is very useful for intensive IO application e. You can select a class idle – best effort – real timethe man page is short and well explained. Every command launched from this shell will have a lover priority. List the processes with jobs. When needed detach from the terminal with disown. Use nohup to start a process which has to keep running when the shell is closed immune to hangups.
See also the program htop from htop. While top is running press the key h for a help overview.
Podręcznik komend linuxa
The default umask is usually The umask is subtracted fromthus umask results in a permission 0f See below and the dd examples. To overcome the file names restrictions: There is a nice documentation with examples on the FreeBSD handbook chapter This can be trimmed with dd. Here we use the vnode 0, but it could also be 1. Note however that this automatic setup will only work if the file image is NOT on the root partition.
Windows Route add Configure additional IP addresses Linux ifconfig eth0 Don’t tell me why you want to change the MAC address For example etherchange http: Or look for “Mac Makeup”, “smac”. Ports in use Listening open ports: The program netstat-nat http: The domain to which the host belongs is also stored in this file.
A minimal configuration is: Firefox and will be unaffected. For example the public DNS server See from which server the client receives the answer simplified answer.
Any entry can be queried and the DNS server can be selected with: This can be done with dighost and nslookup: The format is simple, for example: The file also exists on Windows, it is usually in: The default interface is eth0.
df (Unix) – Wikipedia, wolna encyklopedia
To configure an interface for example bge0 run: Traffic analysis Bmon http: Use windump -D to list the interfaces. Kkmendy with nmap Nmap http: If you don’t scan your servers, hackers do it for you Traffic control QoS Traffic control manages the queuing, policing, scheduling, and other traffic parameters for a network. The following examples are simple practical uses of the Linux and FreeBSD capabilities to better use the available bandwidth. Limit upload DSL or cable modems have a long queue to improve the upload throughput.
It is therefore useful to limit the device upload rate to match the physical capacity of the modem, this should greatly improve the interactivity. Linux For a Kbit upload modem. Using the same pipe number will reconfigure it. For example limit the upload bandwidth to Kbit.
See the full example on voip-info. Suppose VoIP uses udp on ports The default traffic flows into queue 3 and QoS Minimize-Delay flows into queue 2. This is your mask. Mon Sep 24 Here koomendy useful examples, there are many more on the net, for example g-loaded. You might need to use the command netcat instead of nc. Also see the similar unlx socat. File transfer Copy a large folder over a raw tcp connection.
The transfer is very quick no protocol overhead and you don’t need to mess up with NFS or SMB or FTP or so, simply make the file available on the server, and get it from the client. Remote shell Option -e only on the Windows kimendy Or use nc 1. The text is transferred with the enter key. For this example let’s connect host-client to host-serverthe key is generated on the client.
With cygwin you might have to create your home directoy and the. Keys generated by the ssh. This can be done with the ssh-keygen command.
Create a key pair with the ssh. Settings – User Authentication – Generate New
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