Unix Toolbox. Unix Toolbox. 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 explanations, however the reader is supposed to know what s/he is doing. Hardware . See also /etc/issue. If the master. passwd is modified manually (say to delete a password), run # pwd. 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. For example to change the open files limit from. This is only valid within the shell.
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The ulimit command can be used in a script to change the limits for the script only. For example. # cat /etc/security/limits. Limit user processes. Limit application open files. System wide. Kernel limits are set with sysctl. Permanent limits are set in /etc/sysctl.
An unlimited value is still limited by the system maximal value. Permanent limits are set in /etc/sysctl.
The syntax is the same as Linux but the keys are different. Better for apache/sendmail. How many file descriptors are in use. How many open sockets are in use.
Default is 1. 02. See The Free. BSD handbook Chapter 1. And also Free. BSD performance tuninghttp: //serverfault. Solaris. The following values in /etc/system will increase the maximum file descriptors per proc. The scripts are stored in /etc/init. N. d with N the runlevel number.
It is usually 3 or 5. The actual runlevel can be changed with init.
For example to go from 3 to 5. Enters runlevel 5. Shutdown and halt. Single- User mode (also S)2 Multi- user without network.
Multi- user with network. Multi- user with X6 Reboot.
This guide will walk through configuring a pfSense firewall device to use the pfBlockerNG package as well as some basic examples of domain block lists that can. How install Apache 2.4, PHP 5.4 and MySQL 5.5.21 on Windows 7. Why do you think I’m wrong? Just because it has fliead on your system doesn’t make me wrong. Go is a tool for managing Go source code. Usage: go command BEFORE YOU START. I would recommend you first learn qmail via www.lifewithqmail.org. Next do a bit of reading about vpopmail servers : Bill Shupp's Linux Qmail.
Use chkconfig to configure the programs that will be started at boot in a runlevel. Default is to start in 2,3,4 and 5 and shutdown in 0,1 and 6. The final boot state (single user, with or without X) is configured in /etc/ttys. All OS scripts are located in /etc/rc. The activation of the service is configured in /etc/rc. The default behavior is configured in /etc/defaults/rc.
The scripts responds at least to start. For example # init 6 for reboot.
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. You can select the single user mode on the boot menu (option 4) which is displayed for 1.
The single user mode will give you a root shell on the / partition. The solution is to mount the root partition from an other OS (like a rescue CD) and change the password on the disk. To restart the build after an interruption, add the option NO. Boot from a live cd, . Install Oracle Data Mining Repository Idaho. Suppose linux lies on /dev/sda. Misc. Disable OSX virtual memory (repeat with load to re- enable). Faster system, but a little risky.
A list of all running process is retrieved with ps. Negative numbers have a higher priority, the lowest is - 2.
Positive is . Make sure you know if /usr/bin/nice or the shell built- in is used (check with # which nice). This is very useful for intensive IO application (e. You can select a class (idle - best effort - real time), the 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. See also the program htop from htop.
Linux and Free. BSD (ports/sysutils/htop/). While top is running press the key h for a help overview. Useful keys are. u . Use + or blank to see all usersk . The default umask can be changed for all users in /etc/profile for Linux or /etc/login. Free. BSD. The default umask is usually 0. The umask is subtracted from 7.
If listed in /etc/fstab. Or find the device in /dev/ or with dmesg. Free. BSD# mount - v - t cd. If the Free. BSD has many slices, they are the one not listed in the fdisk table, but visible in /dev/sda* or /dev/hda*.
Necessary for fsck for example. Linux. # mount - o ro - u / # Free. BSD. Copy the raw data from a cdrom into an iso image (default 5. Virtualbox. Allow a share on the host.
VBox. Manage sharedfolder add . It now in use. # swapoff /swap. Mount an SMB share. Suppose we want to access the SMB share myshare on the computer smbserver, the address as typed on a Windows PC is \\smbserver\myshare\. We mount on /mnt/smbshare. Warning> cifs wants an IP or DNS name, not a Windows name. Without conv=notrunc, the image will be smaller if there is less content on the cd.
See below and the dd examples. To overcome the file names restrictions: - r enables the Rock Ridge extensions common to UNIX systems, - J enables Joliet extensions used by Microsoft systems. DMA is enabled with the sysctl command and the arguments below, or with /boot/loader. Additionally it is possible to use the native ATAPI interface which is found with.
ATAPI - scanbus. And burn the CD/DVD as above. The examples refer to the dvd device as /dev/dvd which could be a symlink to /dev/scd. Linux) or /dev/cd. Free. BSD) or /dev/rcd. Net. BSD/Open. BSD character SCSI) or /dev/rdsk/c. Solaris example of a character SCSI/ATAPI CD- ROM device).
There is a nice documentation with examples on the Free. BSD handbook chapter 1. This can be trimmed with dd. It is in the Free. BSD ports in sysutils/bchunk. Here we use the vnode 0, but it could also be 1.
Test your setup with # /etc/rc. The reason is that the /etc/rc. Images located outside the root partition will be mounted later with the script /etc/rc. How to create a 6. MB partition mounted on /memdisk. Free. BSD# mount. Don't tell me why you want to change the MAC address..
For example etherchangehttp: //ntsecurity. Or look for . The program netstat- nathttp: //tweegy. The domain to which the host belongs is also stored in this file. A minimal configuration is. Check the system domain name with. Same as dnsdomainname. Windows. On Windows the DNS are configured per interface.
To display the configured DNS and to flush the DNS cache use. Firefox) and will be unaffected. For example the public DNS server 2.
See from which server the client receives the answer (simplified answer). Any entry can be queried and the DNS server can be selected with @.
MX google. com. # dig @1. NS sun. com # To test the local server. NS MX heise. de # Query an external server. AXFR @ns. 1. xname. Get the full zone (zone transfer). The program host is also powerful.
This can be done with dig, host and nslookup. Single hosts can be configured in the file /etc/hosts instead of running named locally to resolve the hostname queries. The format is simple, for example.
The priority between hosts and a dns query, that is the name resolution order, can be configured in /etc/nsswitch. AND /etc/host. conf.
The file also exists on Windows, it is usually in. C: \WINDOWS\SYSTEM3.
DRIVERS\ETCDHCPLinux. Some distributions (Su. SE) use dhcpcd as client. The default interface is eth. To configure an interface (for example bge. The lease with the full information is stored in. Use /etc/dhclient.
Use windump - D to list the interfaces. If you don't scan your servers, hackers do it for you.. The following examples are simple practical uses of the Linux and Free. BSD capabilities to better use the available bandwidth. However filling the queue with a fast device (e. It is therefore useful to limit the device upload rate to match the physical capacity of the modem, this should greatly improve the interactivity. Set to about 9. 0% of the modem maximal (cable) speed.
Pipes are used to set limits the bandwidth in units of . Using the same pipe number will reconfigure it.
For example limit the upload bandwidth to 5. Kbit. See the full example on voip- info. Suppose Vo. IP uses udp on ports 1. The following commands define the Qo. S to three queues and force the Vo. IP traffic to queue 1 with Qo.
S 0x. 1e (all bits set). The default traffic flows into queue 3 and Qo. S Minimize- Delay flows into queue 2.
Find the 2^N ending of the port range, deduce the range and convert to HEX. This is your mask. Example for 1. 00. Mon Sep 2. 4 1. 3: 5. The master server is servername.
Here some 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 command socat.
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. Here 1. 92. 1. 68.
IP address. Or use nc 1. The text is transferred with the enter key.
The idea is to append your public key to the authorized. For this example let's connect host- client to host- server, the key is generated on the client. With cygwin you might have to create your home directoy and the . USER/. ssh. Use ssh- keygen to generate a key pair. Keys generated by the ssh. Open. SSH server. This can be done with the ssh- keygen command.
The key is not protected by a password. To avoid a man- in- the- middle attack the administrator of the server can send you the server fingerprint which is then compared on the first login. Use ssh- keygen - l to get the fingerprint (on the server). However the implementation is very slow.
See fuse sshfshttp: //fuse. This only works with TCP. The general nomenclature for forward and reverse is (see also ssh and NAT example). L localport: desthost: destport user@gate # desthost as seen from the gate. R destport: desthost: localport user@gate # forwards your localport to destination# desthost: localport as seen from the client initiating the tunnel. X user@gate # To force X forwarding.
This will connect to gate and forward the local port to the host desthost: destport. Note desthost is the destination host as seen by the gate, so if the connection is to the gate, then desthost is localhost. More than one port forward is possible. This is the simplest example, desthost is thus localhost, and we use the port 8. Once the ssh session is open, both services are accessible on the local ports. We need access to the smb share and also remote desktop to the server. Furthermore the local RDP is already listening on 3.
For this example let's use a virtual IP of 1. With putty use Source port=1. Color Print Professional Rip Software there.