Piping Comparison & Pattern search commands Grep command Find command Process Management Communication Commands Memory Management Commands Scheduling Jobs via Crontab

1. 
Piping

Comparison & Pattern search commands


Grep command
Find command
Process Management

Communication Commands

Memory Management Commands

Anil Kumar Kapil

7 February 2014
UNIX
Scheduling Jobs via Crontab
Presented by – Anil Kumar Kapil

2. Pipes are UNIX constructs that allow us to send the output of a
command as input to other command

You can redirect the output of one command into the input of another
command by using the pipe symbol „|‟
Example
ls –lrt |grep .html
 ps –ef | grep oracle | sort

Anil Kumar Kapil

7 February 2014
UNIX PIPES

3. 
The grep generalized regular expression parser, tool searches for lines matching a specific pattern
grep [-nvwx] [-number] { expression} [file1 file2 ... fileN]
Examples :
grep Exception logfile.txt Or
cat logfile.txt |grep Exception

$ grep error ../oracle/Test/ECIS/Log/*

grep Exception logfile.txt | grep -v ERROR

searches only for instances of 'ERROR' that are entire words; it does not match `SysERROR„

grep -w ERROR logfile

Use `<' and `>' to match the start and end of words. If you want only words starting from “ERROR”

grep „<ERROR‟ logfile

$ grep hosts /private/etc/* | grep 'Permission denied' > results.txt

Use “ ^” to match the start of line

ls -lrt |grep '^d'
Note : other associated commands with grep are egrep and fgrep. egrep typically runs faster
Anil Kumar Kapil

7 February 2014
GREP COMMAND

4. Syntax
Owners and groups
7 February 2014
FIND COMMAND
Anil Kumar Kapil
Search in multiple directories
Search for older files

5. Search for file type

Looking for files with particular pattern

Searches through only
the /usr and /home directories for any file named
"Chapter1.txt“


List all the files and directories in the box which have
only character in the name


Performing action on the output of find command
find . -name '[a-zA-Z]*.o' –print
Searching for files by permission

If you wanted to look for files that you can execute,
(i.e. shell scripts or programs)

find . -perm -100 -print


find . -iname “Oracle*” -type f
List all the files and directories in the box which
holds the 755 permission in Unix

find . -perm 755 –print
Looking for files by sizes

Find details of files in current directory and subdirectory, greater than 1000 bytes and less than
5000 bytes

find . -size +1000c –size -5000 -exec ls -l {} ;
or
find . -size +1000c –size -5000 | xargs ls –l
Anil Kumar Kapil


find /usr /home -name Chapter1.txt -type
Case sensitive search in the current directory -- and
all subdirectories
7 February 2014
FIND COMMAND

6. 

Acting on files you find (exec && xargs)

This command searches through the /usr/local directory for
files that end with the extension .html. When these files are
found, their permission is changed to mode 644 (rw-r--r--)

expr1 -o expr2
find /usr/local -name "*.html" -type f -exec chmod 644 {} ;
Alternation of expression (-o is the or operator)
! Expression
The negation of a expression

find . -type f -name "Foo*" -exec rm {} ;
or
find . -type f -name "Foo*“ | xargs rm –f
or
find . -type f -name "Foo*" -ok rm {} ;
The following command removes all files in your
home directory named a.out or *.o that have
not been accessed for a week


Find all text file which contains word “Exception”

Description
expr1 [-a] expr2 Concatenation of expression
Find all files under the current directory that begin with the
letters 'Foo' and delete them


Expression
To find all files that don't match a filename pattern

find . –name "*.txt" –print | xargs grep “Exception”

find . -type f ! -name "*.html“
Finding files that contain text (find + grep)

how to find all files beneath the current directory
that end with the extension .java, and contain the
characters StringBuffer.


find . ( -name a.out -o -name '*.o' ) -atime +7 exec rm {} ;
find . -type f -name "*.java" -exec grep -l
StringBuffer {} ;
Owners and groups
Anil Kumar Kapil

Logical Expressions
7 February 2014
FIND COMMAND

7. Any command executed on a UNIX
machine run in it‟s own process

foreground  if you must wait for the
job to finish executing before you
can enter another command

background  a job running in
background does not have to finish
executing before you can enter
another command
By default, ps only tells us the processes
that we start
ps-ef | Lists a full listing.

To run jobs in background
uptime : Show how long the computer is
running

who: displays information about the
USER currently connected


ps : The ps command allows us to look at
the processes currently running on the
machine.



-a use all options
-b Report information about last reboot
-H print headings

/a.sh &
Killing processes


^c  terminates a foreground
process
kill process_id  terminates a
process. The process is specified by
process ID
Anil Kumar Kapil



Types of UNIX job
7 February 2014
PROCESS MANAGEMENT

8. ftp - file transfer program

scp : Secure copy command
Anil Kumar Kapil

7 February 2014
COMMUNICATION COMMANDS
scp afile.txt oracle@10.237.225.78:/cis_app/Projects/

To connect to another networked machine, use the ssh command



ssh –l username remotecomputer
Sftp command ?
telnet command?

9. Du
du (disk usage) will count the amount of disk space
for a given directory, and all its subdirectories take
up on the disk.

Df
df (disk filling) summarizes the amount of disk space
in use.
Anil Kumar Kapil

7 February 2014
MEMORY MANAGEMENT

10. Execute a job in a specific time


Different options of crontab command




Linux Crontab Format

MIN HOUR DOM MON DOW CMD

Field
MIN
HOUR
DOM
MON
DOW
CMD
Description
Minute field
Hour field
Day of Month
Month field
Day Of Week
Command
Allowed Value
0 to 59
0 to 23
1-31
1-12
0-6
Any command to be executed.
Schedule a Job for more than one instance (e.g.
Twice a Day)


00 11,16 * * * /home/ramesh/A.sh
00 – 0th Minute (Top of the hour)
11,16 – 11 AM and 4 PM
* – Every day
* – Every month
* – Every day of the week
This example update the statics of the database
every weekday during the working hours (9 a.m –
6 p.m)

Note: Hour field uses 24 hours format. So, for 8 AM use 8,
and for 8 PM use 20
30 08 10 06 * /home/ramesh/A.sh
30 – 30th Minute
08 – 08 AM
10 – 10th Day
06 – 6th Month (June)
* – Every day of the week
00 09-18 * * 1-5 /home/ramesh/check-db-status
00 – 0th Minute (Top of the hour)
09-18 – 9 am to 12 am, 1 pm to 6 pm
* – Every day
* – Every month
1-5 -Mon, Tue, Wed, Thu and Fri (Every Weekday)
Anil Kumar Kapil

$ crontab -l  See your crontab file
$ crontab –e  Edit your crontab file
$ crontab -u sathiya -l  View Other Linux User‟s Crontab
entries : login to root and use -u {username} –l
Scheduling a Job For a Specific Time Every Day :
This will execute the A.sh shell script on 10th June
08:30 AM
7 February 2014
SCHEDULING JOBS VIA CRONTAB

11. 7 February 2014
Anil Kumar Kapil
QUESTIONS ?

12. 7 February 2014
Anil Kumar Kapil
Thank You ……