Linux

Contents ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

What is Linux ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Where did it come from? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Open Source Software ,[object Object],[object Object]

How do you get it? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Why is it significant? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Logging In ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Logging In ,[object Object],Linux 2.2.13 (penguinvm.princeton.edu) (ttyp1) penguinvm login: neale Password: Last login: Tue Jan 4 10:13:13 from linuxtcp.princeton.edu [neale@penguinvm neale]$

Rule Number 1 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Creating a new user ,[object Object],[object Object],[object Object],[root@penguinvm]# useradd scully [root@penguinvm]# passwd scully Changing password for user scully New UNIX password: Retype new UNIX password: passwd: all authentication tokens updated successfully [root@penguinvm]#

Adding a new user ,[object Object],[object Object],[object Object],[object Object]

Users and Groups ,[object Object],[object Object],[object Object],[object Object],uid=500(neale) gid=500(neale) groups=500(neale),3(sys),4(adm)

Users and Groups ,[object Object],[object Object],[object Object],[object Object],neale sys adm

Using the new user ,[object Object],[object Object],Linux 2.2.13 (penguinvm.princeton.edu) (ttyp2) penguinvm login: scully Password: [scully@penguinvm scully]$

You need help? ,[object Object],[object Object],[object Object],[object Object]

The Linux System User commands includes executable programs and scripts The shell interprets user commands. It is responsible for finding the commands and starting their execution. Several different shells are available. Bash is popular, The kernel manages the hardware resources for the rest of the system.

Linux File System Basics ,[object Object],[object Object],[object Object],/ etc home usr passwd inittab neale scully marty a b Directories User home directories Data files root

Naming Files ,[object Object],[object Object],[object Object],[object Object],/ etc home usr passwd inittab neale scully marty a b /etc/passwd /home/neale/b

The Current Directory ,[object Object],[object Object],[object Object],letter doc/letter ./doc/letter /home/neale/doc/letter / etc home usr passwd inittab neale scully marty a doc Current working directory

Some Special File Names ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Special Files ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Linux Command Basics ,[object Object],ls -l /etc Command name Options (flags) Arguments

Standard Files ,[object Object],[object Object],[object Object],[object Object]

Redirecting Output ,[object Object],ls -l >output “ >” is used to specify the output file

Redirecting Input ,[object Object],wc <input “ <” is used to specify the input file

Connecting commands with Pipes ,[object Object],[object Object],ps aux | grep netscape | wc -l The output of the ps command is sent to grep grep takes input and searches for “netscape” passing these lines to wc wc takes this input and counts the lines its output going to the console Like CMS Pipes, “|” is used to separate stages

Command Options ,[object Object],[object Object],[object Object],[object Object],[object Object]

Common Commands ,[object Object],[object Object],[object Object],[object Object]

File Commands ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

More Commands ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

More Commands ,[object Object],[object Object],[object Object],[object Object],ar -t libgdbm.a __.SYMDEF dbmopen.o

More Commands ,[object Object],[object Object],[object Object]

More Commands ,[object Object],[object Object]

More Commands ,[object Object],[object Object],In this example, we look for files with an extension “c” (that is, C source files). The filenames we find are passed to the xargs command which takes these names and constructs a command line of the form: grep -i fork <file.1>…<file.n> . This command will search the files for the occurrence of the string “fork”. The “ -i ” flag makes the search case insensitve.

More Commands ,[object Object],[object Object],UID PID PPID C STIME TTY TIME CMD root 6715 6692 2 14:34 ttyp0 00:00:00 sleep 10h root 6716 6692 0 14:34 ttyp0 00:00:00 ps -ef [root@penguinvm log]# kill 6715 [1]+ Terminated sleep 10h

More Commands ,[object Object],[object Object],This find s all files in the current and subsequent directories with an extension of c,v. sed then strips the ,v off the results of the find command. xargs then uses the results of sed and builds a grep command which searches for occurrences of the word PATH in the C source files.

More Commands ,[object Object],[object Object],tar -tzf imap-4.7.tar.gz imap-4.7/ imap-4.7/src/ imap-4.7/src/c-client/ imap-4.7/src/c-client/env.h imap-4.7/src/c-client/fs.h

Shells ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Another definition of a Shell ,[object Object],[object Object],[object Object]

Why Do I Care About The Shell? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],#!/bin/bash while true do cat somefile > /dev/null echo . done /* */ do forever ‘ PIPE < SOME FILE | hole’ say ‘.’ end

Switching Users ,[object Object],[object Object],[object Object],[object Object],[object Object]

Environment Variables ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Environment Variables ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Some Important Environment Variables ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

PATH Environment Variable ,[object Object],[object Object],[object Object],[object Object]

PATH Environment Variable ,[object Object],[object Object],[object Object]

File Permissions ,[object Object],[object Object],[object Object],[object Object],[object Object]

File Permissions ,[object Object],[object Object],[object Object],[object Object]

File Permissions ,[object Object],-rwxrwxr-x 1 rvdheij rvdheij 5224 Dec 30 03:22 hello -rw-rw-r-- 1 rvdheij rvdheij 221 Dec 30 03:59 hello.c -rw-rw-r-- 1 rvdheij rvdheij 1514 Dec 30 03:59 hello.s drwxrwxr-x 7 rvdheij rvdheij 1024 Dec 31 14:52 posixuft Permissions Owner Group

Interpreting File Permissions -rwxrwxrwx Other permissions Group permissions Owner permissions Directory flag (d=directory; l=link)

Changing File Permissions ,[object Object],[object Object],chmod 755 file # Owner=rwx Group=r-x Other=r-x chmod 500 file2 # Owner=r-x Group=--- Other=--- chmod 644 file3 # Owner=rw- Group=r-- Other=r-- chmod +x file # Add execute permission to file for all chmod o-r file # Remove read permission for others chmod a+w file # Add write permission for everyone

Links? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Editors ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Linux Device Handling ,[object Object],[object Object],/dev/tty x TTY devices /dev/hdb IDE hard drive /dev/hdb1 Partition 1 on the IDE hard drive /dev/mnda VM Minidisk /dev/dda Channel Attached DASD /dev/dda1 Partition 1 on DASD /dev/null The null device (“hole”) /dev/zero An endless stream of zeroes /dev/mouse Link to mouse (not /390)

Devices and Drivers ,[object Object],[object Object],[object Object],[object Object],brw-r--r-- 1 root root 64, 0 Jun 1 1999 /dev/mnda crw-r--r-- 1 root root 5, 0 Jan 5 09:18 /dev/tty Major no. Minor no. Device Type: b - block c - character

Special Files - /proc ,[object Object],cat /proc/cpuinfo vendor_id : IBM/S390 # processors : 1 bogomips per cpu: 86.83 processor 0: version = FF, identification = 045226, machine = 9672

File Systems ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

File Systems ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

File Systems ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Virtual File System ,[object Object],[object Object],[object Object]

Virtual File System ,[object Object],[object Object]

Virtual File System ,[object Object],[object Object],[object Object],[object Object],[object Object]

Processes ,[object Object],[object Object],[object Object],[object Object]

Processes ,[object Object],[object Object],[object Object],[object Object],UID PID PPID C STIME TTY TIME CMD root 5 1 0 1999 ? 00:00:14 [kswapd] bin 254 1 0 1999 ? 00:00:00 [portmap] root 307 1 0 1999 ? 00:00:23 syslogd -m 0 root 350 1 0 1999 ? 00:00:34 httpd

Processes [root@penguinvm log]# sleep 10h & [1] 6718 [root@penguinvm log]# ps -ef UID PID PPID C STIME TTY TIME CMD root 6718 6692 0 14:49 ttyp0 00:00:00 sleep 10h & causes process to be run in “background” Job Number Process ID (ID) Parent Process ID

Processes - UID & GID ,[object Object],[object Object],[object Object],[object Object]

Processes - UID & GID ,[object Object],[object Object],[object Object],[object Object],[object Object]

Processes - Process Groups ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Processes - PID ,[object Object],[object Object],[object Object],[object Object]

Processes - PGID ,[object Object],[object Object],[object Object],[object Object]

Processes - PPID ,[object Object],[object Object],[object Object],[object Object]

Security Guidelines ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Security Guidelines ,[object Object],[object Object],[object Object],[object Object],[object Object]

Security - Important Files /etc/passwd - password file /etc/shpasswd - shadow password file /etc/group -lists groups and users contained in groups /etc/services - lists network services and their ports /etc/ftpusers - contains list of accounts that cannot use ftp /etc/hosts.equiv - generic list of remote users ~/.rhosts - list of remote users for a specific account /etc/hosts - host definition list /etc/hosts.lpd - hosts who can use remote printing /etc/hosts.allow - lists services that remote users are allowed to use /etc/hosts.deny - lists services tthat remote users are not allowed to use /etc/nologin - no login message that also disables logins /etc/securetty - lists legal terminals for root to login from /etc/exports - lists locations that can be remotely accessed via NFS /etc/syslog.conf - configures the syslog facility /etc/inetd.conf - configures inetd

Linux/390 Specifics ,[object Object],[object Object],[object Object],[object Object],[object Object]

Linux/390 Specifics ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Linux in the Business World Issues and observations

Linux’s place in the market ,[object Object],[object Object],[object Object],[object Object]

Linux’s place in the market ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Linux’s place in the market ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Linux’s place in the market ,[object Object],[object Object],[object Object],[object Object],[object Object]

Linux’s place in the market ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

IBM Software Announcements ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Linux Available Commercial Software

Website Development ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Databases ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Data Visualization and CAD ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Development Tools ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Emulation Tools ,[object Object],[object Object],[object Object]

Financial Software ,[object Object],[object Object]

Libraries ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Mathematics ,[object Object],[object Object],[object Object],[object Object]

Multimedia ,[object Object],[object Object],[object Object],[object Object],[object Object]

Network Servers ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Office Tools ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Text Processing ,[object Object],[object Object]

System Administration ,[object Object],[object Object],[object Object]

X Windows Related ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Other Software ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Additional Resources ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Additional Resources ,[object Object],[object Object],[object Object]

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