Overview of Linux based Utilities

Understanding UNIX/Linux Utilities

•UNIX/Linux utilities let you

–Create and manage files
–Run programs

–Produce reports

–Monitor and maintain the system

–Recover from a range of errors

•New utilities are continually being added in order to make UNIX/Linux run more efficiently

•Classified into eight major areas:

–File processing

–System status

–Networking

–Communications

–Security

–Programming

–Source code management

–Miscellaneous

File processing

Command     Brief description of functions

·         awk- Processes files

·         cat- Displays files(and is used with other tools to concatenate files.)

·         cmp- Compares two files

·         comm- Compares sorted files and shows differences.

·         cp- Copies files

·         cut- Selects characters or fields from input lines.

·         dd- Copies and converts input records

·         diff- Compares two text files and shows differences

·         dump- Backs up files

·         file- Displays the file type.

grep, Less,head, in lpr, tailman,mkdir,mount,mv,pste,pr,pwd,rm,rmdir,sort, tar, touch,wc etc.

System Status Utilities

Command     Brief description of function

·         date    Sets and displays date and time

·         df         Displaces the amount of free space remaining on disk.

·         du       Summarizes file space usage

·         finger  Displays detailed information about user who are logged in.

·         free     Displays amount of free and used memory in the system

·         kill       Terminates a running process

·         ps        Displays process status by process identification number and name

·         sleep  Suspends process execution for a specific time.

Top, uname, w, who,date,df,du,file,etc.

Network Utilities

•         ifconfig – sets up a network interface card

–        Can be used to troubleshooting networking

•         netstat – shows network connection information

•         ping – establishes connectivity to a remote device

•         route – displays routing table information

ftp,rcp,rlogin,rsh,showmount,telnet,wvdial

Communications Utilities

•         mail – sends e-mail

•         mesg n – denies any real-time messages

•         mesg y – accepts any real-time messages

•         talk – allows users to simultaneously ‘chat’ with other logged in users.

•         wall – sends a message to all logged-in users.

•         write – sends a message to a user

Security Utilities

•         chgrp – changes the default group associated with a file

•         chmod – changes the access permissions of a file or directory

•         chown – changes the owner of a file or directory

•         Ipchains-manages a firewall and packet filtering

•         passwd- changes a password.

Programming and Source Code Management Utilities

·         Configure- configures program source code automatically.

·         g++- compiles a c++ program

·         gcc- compiles a c program

·         make- maintains a program source code

·         patch- update source codes.

·         Ci, co, cvs, rcs, rlog etc.

Miscellaneous Utilities

·         at- executes a command or script at a specific time

·         atq- Shows the jobs already scheduled to run.

·         cal- displays the calendar of a month or a year.

·         cd- changes to a directory.

·         tr- replaces specific characters

atrm,batch,expr,fsck,tee,tty, xargs etc.