Introduction to the Linux Command Line

Transcription

1 Introduction to the Linux Command Line May, 2015

2 How to Connect (securely) ssh sftp scp Basic Unix or Linux Commands Files & directories Environment variables Not necessarily in this order.?

3 Getting Connected ssh Secure Shell Provided with Mac OS X and Linux ssh -Y username@somehost.ace-net.ca Windows users need PuTTY or MobaXterm download.html

4 Login If you have a Mac or a Linux machine, open a terminal window and type: > ssh userid@host.ace-net.ca If you have MobaXterm or PuTTY, create a new SSH session for an ACENET cluster, one of: fundy.ace-net.ca glooscap.ace-net.ca mahone.ace-net.ca placentia.ace-net.ca

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7 Looking Around pwd ls print working directory where am I? list what files are here? what subdirectories?

8 Directories Grow on Trees Okay upside down trees! /home/rdickson/new rdickson thesis code.c data more_ data Just files within folders within folders, except we call the folders directories.

9 Getting Around mkdir newdir cd directory cd.. make directory change directory.. means parent directory or one level up. means right here ~ means my home directory

10 Create An (Empty) Directory $ mkdir workshop $ cd workshop $ ls $ pwd /home/rdickson/workshop $

11 Moving Stuff Around mv from to move, also rename cp from to copy rm file remove Careful --- There's no recycle bin! rmdir directory

12 Paths, Directories, Abbreviations Directory separator is / /home/jsmith/code/test is an absolute path begins with / code/test is a relative path no / at the beginning same thing if pwd is /home/jsmith * (asterisk) wildcard, expands to matching filenames

13 Get Some Files $ pwd /home/rdickson/workshop $ cp /home/rdickson/new/rdickson/*. $ ls data more_data

14 What s Inside? cat file more file less file Scroll through file, one screen at a time Spacebar to continue, q to quit, b to back up Editors vim file emacs file or use your computer and transfer with sftp

15 File Permissions Sometimes you need to edit the permissions of a file. The permissions of a file dictate who can execute, read and write to a file. If you do ls - l you might see something like the following: -rwxr-xr-x 1 staveley TechTeam 271 Jul Makefile Third group of 3: What everyone else can do Second group of 3: What group members can do First group of 3: what you (owner) can do --- read, write, execute?

16 File Permissions u - user g - group o - others a - all +r +rw +rwx +x +rx -r -rw -rwx -x -rx To see a directory listing you must have execute permission To change permissions, use chmod $ chmod g+rwx some_file

17 What will happen if I...? which program shows absolute path of program echo $PATH find what directories are searched for executables? $PATH is an environment variable Locates files Example : find./ -name ch*

18 Storage Management quota your disk space limits du - disk usage - how much disk space is being used by the current directory du -h - human readable df - how much disk space is available

19 Data From the Outside World Or from one cluster to another sftp Secure File Transfer Protocol Provided with Mac OS X and Linux sftp username@somehost.ace-net.ca Easiest way to move data between clusters MS Windows? Use MobaXterm or WinSCP

20 WinSCP

21 sftp Commands ls List files already there put filename Copy file from here to there Can use wildcards: put * copies everything get filename cd directory Change directory there lcd directory Local cd, change directory here

22 Where To Go For Help man command manual man -k keyword searches online manual pages Online Linux tutorials Google Unix command line tutorial

23 Where Else To Go For Help ACENETUser Wiki User support line