1. Linux 201 Training Module
Linux Adv File Mgmt

2. This presentation will cover the following topics
PATH Concept ln
which
cut
sort, uniq
diff
find
grep options Redirection >, | , tee
chown, chgrp

3. PATH
PATH is an environmental variable in Linux that tells the shell which directories search for executable files in response to commands issued by a user.
$] echo $PATH
/opt/apache-maven /bin:/home/netstorm/work/bin:/home/n etstorm/work/tools:/bin:/apps/java/jdk1.6.0_ 24/bin:/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr /local/bin:/opt/cavisson/monitors/bin:/usr/lib 64/qt- 3.3/bin:/usr/local/bin:/bin:/usr/bin:/usr/local /sbin:

4. ln command To make a symbolic link : ln /original/file /new/link
This makes /original/file and /new/link the same file - edit one and the other will change. The file will not be gone until both /original/file and /new/link are deleted.
To make a soft symbolic link :
ln -s /original/file /new/link

5. which command Locate a command shows the full path of commands.
$ which cat
/bin/cat

6. cut command Cut out selected fields of each line of a file.
name=`who am i | cut -f1 -d' '`
Set name to current login name.

7. sort command sort lines of text files Sort a file in ascending order
$ sort names.txt
Sort a file in descending order
$ sort -r names.txt

8. Uniq comand remove duplicate lines from a sorted file
sort myfile | uniq
eliminates duplicate lines from the stream (the symbol "|" pipes the output from sort myfile to the uniq command).

9. diff command diff - find differences between two files
$]diff from-file to-file

10. find command find - search for files in a directory hierarchy
find / -name game
Looks for a file named "game" starting at the root directory 
find /usr -name *stat
Find every file under the directory /usr ending in "stat".

11. Grep Options Search for a string in a file grep "Error" logfile.txt
Case insensitive search
grep -i "UNix" file.txt
Specifying the search string as a regular expression pattern.
grep "^[0-9].*" file.txt
This will search for the lines which starts with a number.

12. Checking for the whole words in a file.
grep -w "world" file.txt
The -w option to grep makes it match only the whole words.
Searching for a sting in all files recursively
grep -r "string" *
Displaying the count of number of matches.
grep -c "sting" file.txt

13. redirection
By default, standard output directs its contents to the display. To redirect standard output to a file, the ">" character is used like this:
me]$ ls > file_list.txt

14. Pipes
With pipes, the standard output of one command is fed into the standard input of another. E.g
me]$ ls -l | less

15. Tee command
Read from an input and write to a standard output and file.
ls *.txt | wc -l | tee /dev/tty count.txt
In the above example the ls command would list all .txt files in the current directory, take a word count (wc) by the amount of lines (-l) and the output displayed to the /dev/tty (terminal) will be sent to the count.txt.

16. chown & chgrp command
To change the owner of a file/directory, use the chown command
$ chown newowner file/dir
To change the group of a file/directory, use the chgrp command.
$ chgrp newgroup file/dir
Both chown and chgrp support the -r option for recursively changing the owner or group of an entire subdirectory