some linux commands

 

• chown user path – Change owner of file or directory
• chown user:group – Change owner and group of file or directory
• chown -R user dir – Change owner of directory and contents (recursively)
• chgrp
• cat file – Display the contents of file
• more file – Display file one page at a time; press spacebar to proceed to the next page
• less file – less is similar to more, but also allows moving backwards
• head -20 file – Display the first 20 lines of file
• tail -f file – Display the contents of file as it grows – This is especially usefull for following log files.
• vi, vim, nano, pico, emacs
• which command – give the full path to command
• find dir -type f -name 'foo*' – find all files in dir whose name starts with “foo” (note the single quotes, otherwise shell globing would occur)
• find . -type f -exec grep -l "foo" {} \; – find all files in the current directory containing “foo”
• locate file – find file
• diff -u file1 file2 – view the differences between two files
• diff -ur dir1 dir2 – view the differences between two directories

File System and Partitioning

• mount, umount
• lsblk, blockdev, fdisk, fsck, mkfs, resize2fs

Text and Stream Processing

• strings file – print all human readable strings in a binary file
• grep pattern file – find all lines in file that contain or match pattern
• dd
• pv, tee
• sed, awk, tr, cut, join, column, iconv
• wc -l file – count number of line in file
• nl, od, sort, uniq, fold, tac
• csplit, split
• xargs

File Compression

• tar zcvf archive.tar.gz files... – create a gzip-compressed archive
• tar zxvf archive.tar.gz – decompress and extract archived files to current directory
• gzip file.txt – compresses a file (creates file.txt.gz) and removes the original, uncompressed version
• gunzip file.txt.gz – uncompresses a file that was compressed with gzip or compress and removes the compressed version
• zip -r archive.zip files... – create a zip archive
• unzip archive.zip [-d destination_folder] – extract/decompress zip achive
• unzip -l archive.zip – list the contents of archive.zip
• zcat, zless, zmore, zgrep, zdiff – these ‘Z’ commands operate on gzip-compressed files and provide a ‘Z’ equivalent to their regular counterparts
  • zcat system.log.0.gz – view a compressed file
    • zcat is identical to gunzip -c
  • zless system.log.0.gz – ‘Z’ equivalent of less to view a compressed file

  Getting Help

  • man command – Show the manual for command
  • help command – Use help for builtin commands
    • If you do not know if a command is a shell builtin or not, run type command.
  • info command – for GNU/Linux commands, info often provides a more detailed documentation than the man page
  • apropos subject – Search manual pages for subject
    • man -k is equivalent to the apropos command
  • whatis command – Display one-line manual page descriptions
    • use help -d for a one-line description of a shell builtin
  • which command – Show the full path of a command
  • whereis command – locate the binary, source, and manual page files for a command

  Process Management

  • ps aux – list all processes on the system
  • top, pstree
  • kill, pkill, killall
  • disown, nohup
  • lsof, fuser

  Managing System Services

  • service, systemctl
  • init, shutdown

  User Management

  • usermod, useradd, adduser, userdel, passwd
  • groupmod, groupadd, gpasswd
  • whoami – Show who you are logged in as
  • id, getent, groups
  • who, w, last

  Network Commands

  • ifconfig – List IP addresses and configuration of network interfaces
  • ifdown, ifup
  • dhclient -r eth0 – release current DHCP lease
  • dhclient -v eth0 – obtain IP address from DHCP
  • ip, route
  • iptables
  • wpa_supplicant
  • iwlist – display information about wireless networks
  • wpa_cli
  • brctl, hostapd
  • wget, curl
  • ftp
  • scp -P 5010 foo.txt user@adams204xx.hofstra.edu:/home/user/ – copy local file to linux home directory
  • scp -P 5010 user@adams204xx.hofstra.edu:/home/user/foo.txt foo.txt – copy remote file to local system
  • sftp, tftp, rsync
  • ping, nmap, traceroute, arp, tcpdump
  • nslookup domain – Perform DNS lookup of domain
  • dig domain – Perform DNS lookup of domain
  • ssh user@host – Connect to host as user
  • ssh-keygen -t rsa -b 4096 – Generate a new SSH key-pair
  • ssh-copy-id user@host – Copy your local key (usually ~/.ssh/id_rsa.pub by default) to the account for user on host to enable key-based (passwordless) authentication into the remote host

  System Information

  • uname -a – Show kernel information
  • dmidecode
  • lscpu, lspci, lsusb
  • hostname
  • date, uptime
  • free – Show memory and swap usage

  Printing

  • lp, lpr

  Environment

  • env, chroot

  Shell builtins

  • cd, pwd
  • clear
  • exit
  • history, fc
  • type

  from https://cs.hofstra.edu/docs/pages/reference/commands.html 

  related post: https://briteming.blogspot.com/2019/06/linux.html