echo
echo is used to display a message on the screen and write the given message to standard output with a newline at the end. echo is implemented as built-in command in many command shells like bash, ksh, csh.
$ echo "Hello World"
Hello World
$ echo Hello World
Hello World
Useful Options / Examples
Example command
echo output can be redirected into a file for easy use.
$ echo Hello World > example.txt
$ cat example.txt
Hello World
Example command
echo -n is a useful flag if you don’t want the trailing newline after the string
$ echo -n "Hello World." ; echo " There is no new line before me."
Hello World. There is not new line before me.
Example command
echo can also be used with pattern matching. The following command line will show all the cpp files under current directory.
$ echo *.cpp
The following command line will show all the files under current directory.
$ echo *
Example command
‘echo’ can be used to show the environment value. The following command line will show user’s PATH environment variable.
$ echo $PATH
Example command
echo -e flag is used to enable the backslash-escaped characters in following table:
$ echo -e -n "Hello World.\nThis is a new line.\n"
Hello World.
This is a newline.
| | Backslashescaped characters |
|-------|:----------------------------------------------------------------------------------------------------------:|
| \\ | a literal backslash character ("\"). |
| \a | An alert. |
| \b | Backspace. |
| \c | Produce no further output after this. |
| \e | The escape character; equivalent to pressing the escape key. |
| \f | Form feed |
| \n | New line |
| \r | Carriage Return |
| \t | Horizontal tab |
| \v | Vertical tab |
| \NNN | The character whose ASCII code is NNN(octal); if NNN is not a valid octal number, it is printed literally. |
| \xnnn | The character whose ASCII code is the hexadecimal value nnn. |