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Difference between revisions of "Linux-Commands"
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===Search=== | ===Search=== | ||
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+ | '''$ grep pattern files''' - search for pattern in files | ||
+ | '''$ grep -r pattern dir''' - search recursively for pattern in dir | ||
+ | '''$ locate file''' - find all instances of file | ||
+ | '''$ find /home/tom -name 'index*'''' - find files names that start with "index" | ||
+ | '''$ find /home -size +10000k''' - find files larger than 10000k in /home | ||
===Login (ssh and telnet)=== | ===Login (ssh and telnet)=== |
Revision as of 09:36, 31 March 2014
Contents
System Commands
$ uname –a - display linux system information $ uname –r - display kernel release information $ uptime - show how long system running + load $ hostname - show system host name $ hostname -i - display the IP address of the host $ last reboot - show system reboot history $ date - show the current date and time $ cal - show this month calendar $ w - display who is online $ whoami - who you are logged in as $ finger user - display information about user
$ dmesg - detected hardware and boot messages $ cat /proc/cpuinfo - CPU model $ cat /proc/meminfo - hardware memory $ cat /proc/interrupts - lists the number of interrupts per CPU per I/O device $ lshw - displays information on hardware configuration of the system $ lsblk - displays block device related information in Linux $ free -m - used and free memory (-m for MB) $ lspci -tv - show PCI devices $ lsusb -tv - show USB devices $ lshal - show a list of all devices with their properties $ dmidecode - show hardware info from the BIOS $ hdparm -i /dev/sda -show info about disk sda $ hdparm -tT /dev/sda - do a read speed test on disk sda $ badblocks -s /dev/sda - test for unreadable blocks on disk sda
Statistics and Analyze
$ top - display and update the top cpu processes $ mpstat 1 - display processors related statistics $ vmstat 2 - display virtual memory statistics $ iostat 2 - display I/O statistics (2sec Intervals) $ tail -n 500 /var/log/syslog - last 10 kernel/syslog messages $ tcpdump -i eth1 - capture all packets flows on interface eth1 $ tcpdump -i eth0 'port 80' - monitor all traffic on port 80 ( HTTP ) $ lsof - list all open files belonging to all active processes $ lsof -u testuser - list files opened by specific user $ free –m - show amount of RAM $ watch df –h - watch changeable data continuously
Users
$ id - show the active user id with login and group $ last - show last logins on the system $ who - show who is logged on the system $ groupadd admin - add group "admin" (force add existing group) $ useradd -c "Joe Smith" -g admin -m joe - Create user "joe" and add to group "admin" $ userdel joe - delete user joe (force,file removal) $ adduser joe - add user "joe" $ usermod - modify user information
File Commands
$ ls –al - display all information about files / directories $ ls -alR - display all information about files / directories recursively $ pwd - show current directory path $ mkdir directory-name - create a directory $ rm file-name - delete file $ rm -r directory-name - delete directory recursively $ rm -f file-name - forcefully remove file $ rm -rf directory-name - forcefully remove directory recursively $ cp file1 file2 - copy file1 to file2 $ cp -r dir1 dir2 - copy dir1 to dir2, create dir2 if it doesn’t exist $ mv file1 file2 - move files from one place to another $ ln –s /path/to/file-name link-name - create symbolic link to file-name $ touch file - create or update file $ cat > file - place standard input into file $ more file - output the contents of file $ head file - output the first 10 lines of file $ tail file - output the last 10 lines of file $ tail -f file - output the contents of file as it grows starting with the last 10 lines $ gpg -c file - encrypt file $ gpg file.gpg - decrypt file
Process Related
$ ps - display your currently active processes $ ps aux | grep 'telnet' - find all process id related to telnet process $ pmap - memory map of process $ top - display all running processes $ kill pid - kill process with mentioned pid id $ killall proc - kill all processes named proc $ pkill processname - send signal to a process with its name $ bg - resumes suspended jobs without bringing them to foreground $ fg - brings the most recent job to foreground $ fg n - brings job n to the foreground
File Permission Related
$ chmod octal file-name - change the permissions of file to octal , which can be found separately for user, group and world; octal value 4 -read 2 –write 1 –execute $ chown owner-user file - change owner of the file $ chown owner-user:owner-group file-name - change owner and group owner of the file $ chown owner-user:owner-group directory - change owner and group owner of the directory
Network
$ ifconfig –a - display all network ports and ip address $ ifconfig eth1 mtu 9000 up - set mtu to 9000 $ ifconfig eth0 - display specific ethernet port ip address and details $ ifconfig -a | grep HWaddr - display MAC address
change MAC address: # ifconfig eth0 down # ifconfig eth0 hw ether 00:80:48:BA:d1:30 # ifconfig eth0 up
$ ip addr show - display all network interfaces and ip address (available in iproute2 package,powerful than ifconfig) $ ip address add 192.168.0.1 dev eth0 - set ip address $ ethtool eth0 - linux tool to show ethernet status (set full duplex , pause parameter) $ mii-tool eth0 - linux tool to show ethernet status (more or like ethtool) $ ping host - send echo request to test connection (learn sing enhanced ping tool) $ whois domain - get who is information for domain $ dig domain - get DNS information for domain (screenshots with other available parameters) $ dig -x host - reverse lookup host $ host google.com - lookup DNS ip address for the name $ hostname –i - lookup local ip address (set hostname too) $ wget file - download file (very useful other option) $ netstat -tupl - listing all active listening ports(tcp,udp,pid)
WiFi related: $ iwconfig wlan0 essid "mynetworkESSID" - specify ESSID for the WLAN $ dhclient wlan0 - to receive an IP address, netmask, DNS server and default gateway from the Access Point $ iwconfig wlan0 mode managed key [WEP key] - 128 bit WEP use 26 hex characters, 64 bit WEP uses 10 $ iwconfig wlan0 mode master - set the card to act as an access point mode $ iwconfig wlan0 mode managed - set card to client mode on a network with an access point $ iwconfig wlan0 mode ad-hoc - set card to peer to peer networking or no access point mode $ iwconfig wlan0 mode monitor - set card to RFMON mode $ iwconfig wlan0 essid any - with some cards you may disable the ESSID checking $ iwconfig wlan0 key 1111-1111-1111-1111 - set 128 bit WEP key $ iwconfig wlan0 key off - disable WEP key $ iwconfig wlan0 key open - sets open mode, no authentication is used and card may accept non-encrypted sessions $ iwlist wlan0 scan - give the list of Access Points and Ad-Hoc cells in range (ESSID, Quality, Frequency, Mode etc.) $ iwlist wlan0 power - list the various Power Management attributes and modes of the device $ iwlist wlan0 txpower - list the various Transmit Power available on the device $ iwlist wlan0 retry - list the transmit retry limits and retry lifetime on the device
Compression / Archives
$ tar cf test.tar test - create tar named test.tar containing test/ $ tar xf test.tar - extract the files from test.tar $ tar czf test.tar.gz test - create a tar with gzip compression $ gzip test - compress file and renames it to test.gz
Install Package
$ rpm -i pkgname.rpm - install rpm based package $ rpm -e pkgname - remove package
Install from source $ ./configure $ make $ make install
$ apt-get update - re-synchronize the package index files from their sources $ apt-get upgrade - install the newest versions of all packages currently installed on the system from the sources $ apt-get install package - install package $ apt-get remove package - remove package $ apt-cache search package - search for package
Search
$ grep pattern files - search for pattern in files $ grep -r pattern dir - search recursively for pattern in dir $ locate file - find all instances of file $ find /home/tom -name 'index*' - find files names that start with "index" $ find /home -size +10000k - find files larger than 10000k in /home
Login (ssh and telnet)
File transfer
Disk Usage
Directory
Keyboard shortcuts
Alt+Ctrl+T - open Terminal Window
Alt+Ctrl+L - lock the screen Alt+Ctrl+Del - logoff
Alt+F4 - close current window Alt+F2 - pop up command window (for quickly running commands)
Super-W - show all windows in the current workspace Ctrl+Super+D - show desktop
Ctrl+A - select all items on list or text Ctrl+C - copy all selected items to clipboard Ctrl+X - cut all selected items to clipboard Ctrl+V or Mouse middle button click - paste all selected items to clipboard
PrintScr - takes screenshot Alt+PrintScr - takes screenshot of windows Shift+PrintScr - takes screenshot of selected window area