2. Pipe
Pipe is a mechanism in which output of one
command can be redirected as input to
another command.
General format
Command 1|Command 2
Output of one command 1 is sent to input of
command2
3. Example
$ who > userlist.txt
$ wc –l userlist.txt
If we use pipe mechanism then there is no
need to create temporary file.
$ who | wc -l
4. REDIRECTION:
Linux treats the keyboard as the standard input
(value 0) and terminal screen as standard output
(value 1) as well as standard error (value 2).
We can also take input from sources other than
the keyboard and output can be passed to any
source other than the terminal screen. Such a
process is called as “redirection”.
5. REDIRECTION:
The ‘<’ symbol is used to redirect inputs,
the ‘>’ symbol is used to redirect outputs
and ‘2>’ symbol is used to redirect error
messages.
7. FILTERS:
There are some Linux commands that
accept input from standard input or files,
perform some manipulation on it, and
produces some output to the standard
output. These are called as “filters”.
15. grep filter
The grep filter searches a file for a particular
pattern of characters, and displays all lines
that contain that pattern.
(grep stands for globally search for regular
expression and print out).
General format
grep [options] pattern [files]
23. more
If the information to be displayed on the screen is
very long, it scrolls up on the screen fastly. So, the
user cannot be able to read it.
This more command is used to display the output page
by page (without scrolling up on the screen fastly).
Use [spacebar] or [f] key to scroll forward one
screen, use [b] key to scroll backward one screen, use
[q] key to quit displaying.
28. paste
This command concatenate the content of
the specified file into single file vertically.
Cut command separates the columns paste
command merges the column.
General format
paste <filename1><filename2>...
29.
30. tr
This command is used to change the case
of alphabet
General format
<tr> <Characterset1><Characterset2><Standard Input>
