Checklist : the main commands on UNIX

With Raspberry Pi, Some are discovering the world of Linux and more generally UNIX. Then this article is here to give you some tips/reminders for your manipulations under the console or SSH.

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Find data

  • whereis : know where to find a file. Ex: whereis ls
  • which : What program will be executed by the shell when calling. It allows to find if a program is in several places. Ex: which ls
  • grep : search for a string in a file. Ex: grep <string> <file name>
  • egrep : as grep but allows searching with regular expressions.
  • find : searches files according to certain criteria. Can execute a command file find. Ex: find . -name “*.Java” -exec grep System {} \;

Find help

  • man : gives help on a program, a function. Install the package man

Manage files

  • MV : move a file. Ex: MV <file name> <new file name>
  • CAT : display the contents of a file. Ex: CAT <file name>
  • file : Displays the type of the file. Useful when it is not known how the file will be interpreted. Ex: file <file name>
  • CP : copy the file to another. Ex: CP <file name> <new file name>
  • touch : creating a file empty. Ex: touch <new file>

Manipulate directories

  • pwd : Displays the current directory
  • cd : move to a directory. Without parameters returns in the home directory of the logged in user
  • mkdir : creating a directory
  • rmdir : deleting a directory empty
  • RM-r : recursively delete a non-empty same directory. Attention 😉

Filter the information

  • more : display the contents of a file, page by page. Ex: more <file name>
  • less : as the command more with the possibility to return back. Ex: less <file name>
  • head : display the first lines of a file. Ex: head -50 <file name>
  • tail : display the last lines of a file. Ex: tail -50 <file name>
  • fate : sort the rows of a file based on the settings. Ex: fate <file name>
  • uniq : delete multiple lines in a file. Ex: uniq <file name>
  • column : organizes data into columns. Ex: Mount | column t
  • diff : will generate a report containing the differences between two files. Ex: diff <file A> <file B>
  • WC : count the number of lines/characters/words. Ex: WC <file name>

Manipulate the process

  • PS : Displays information about running processes. Select the type of information and filter settings.
  • Ptree : Show processes, their parent, the parameters used. Install the package zsh
  • kill : sending a signal to a process. The 15 request a clean shutdown of the process, the 9 It stops suddenly. Ex : kill -9 12345
  • top : Displays the information of the system and running processes. Cooling is automatic. A set of filters and sorting is configurable.

Information on the environment

  • Mount : mount a partition on the system. Without parameter, Displays the mounted partitions/drives.
  • DF : Displays the capacity and rate of occupancy of the partitions and mounted disks.
  • the : calculating the size of a directory including sub directories.
  • mpstat : Displays a set of statistics on a process. Install the sysstat package
  • iostat : Displays a set of statistics on the use of CPU and the system reads/writes. Install the sysstat package
  • nfsiostat : Displays a set of statistics on the use of the CPU and reads/writes of the NFS partitions. Install the sysstat package
  • fsck : perform a consistency of a partition or disk check (not mounted).

The list is far from complete (It is not the purpose of). If you see other important, feel free to share in the comments.

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