Unix training session 3
4 likes739 views
The document discusses various Unix commands and their functionalities, including piping, the grep command for searching patterns, and the find command for locating files. It also details process management commands, memory management, and scheduling jobs using crontab. Introduced by Anil Kumar Kapil on February 7, 2014, the document serves as a guide for managing and executing commands in a Unix environment.
![
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](https://image.slidesharecdn.com/unixtraining-session3-140207040149-phpapp01/85/Unix-training-session-3-3-320.jpg)
![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](https://image.slidesharecdn.com/unixtraining-session3-140207040149-phpapp01/85/Unix-training-session-3-5-320.jpg)
![
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](https://image.slidesharecdn.com/unixtraining-session3-140207040149-phpapp01/85/Unix-training-session-3-6-320.jpg)
Unix training session 3
- 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 ……