* First of all let look the below

Code:

# echo \h\h\h\h
hhhh

\ --> does no effect to echo


* Anyway

Code:

 
# echo \++
++

first \ char is meaningless in here and echo after \ chars so \++

so echo already write on the newline

Code:

  \ is same --> echo \

Code:

 
# echo A
A
# echo \A
A

but the trick for use ""
use this to remove its special meanings

Code:

# echo "A"
A
# echo "\A"
\A

Anymore \ is calculating with "" too

Code:

 
# echo \\\\\++
\\++

\ and \\\\++
so echo \\\\++ --> is to be \\++
\\ \\ --> two backslah is mean (one backslah) + two backslah is mean (one backslah) --> one + one = two backslah ( \\ )

Code:

 
# echo "\\\\\++"
\\\++

"\" and \\\\++
so echo \\\\++ --> is to be \\\++
\\ \\ --> two backslah is mean (one backslah) + two backslah is mean (one backslah) --> one + one = two backslah ( \\ )
\\ plus "\" --> \\\ three backslah and ++ ---> \\\++





Now in examples

1-)

Code:

 
# echo \\++
\++

\ and \++
first \ char doesnt change in the output
so echo \++

2 -)

Code:

 
# echo \\\++
\++

\ and \\++
first \char .....
so echo \\++ --> is to be \++
because two \\ originally is one \
\\ --> \

3-)

Code:

 
[root@XXXx ~]# echo \\\\++ 
\\++

\ and \\\++
first \char .....
so echo \\\++ --> is to be \\++
\\ \ --> two backslah is mean (one backslah)+ one backslah --> one + one = two backslah ( \\ )

4-)

Code:

 
[root@XXXx ~]# echo \\\\\++
\\++

\ and \\\\++
so echo \\\\++ --> is to be \\++
\\ \\ --> two backslah is mean (one backslah) + two backslah is mean (one backslah) --> one + one = two backslah ( \\ )


* Eval ; so eval removes the first backslash..

Code:

 
[root@XXXx ~]# eval echo \\++ 
++

---> eval removes the backslash and echo processing..

Code:

 
[root@XXXx ~]# eval echo \\\++ 
++

---> eval removes the backslash and echo processing..

Code:

 
[root@XXXx ~]# eval echo \\\\++ 
\++

---> eval removes the backslash and echo processing..



Regards
ygemici