Single-line and multiline comments in the shell

2017-10-04 Add background account:

Suse10, Huawei Veneer, the first four methods are small white in the actual Linux environment test results, may be the difference between Linux version, and not all scenarios are compatible ... Another small white 201 May-January has been formally transformed into Java development, the existing company's information security is not csdn, some feedback compared with the delay ... It is hereby stated that ....

1. Single note

As we all know, # like to comment: Echo ' ni '

# echo ' ni '

2. Multi-line Comment:

Law I:

: <<!

Statement 1

Statement 2

Statement 3

Statement 4

!

For example:

LINUX101:/HOME/WSJ # sh Dian
Ni
Ni
Ni
Ni
Ni
Ni

LINUX101:/HOME/WSJ # More Dian
#!/bin/ksh
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"

: <<!
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
!

Law II:

: '

Statement 1

Statement 2

Statement 3

Statement 4

'

For example:

LINUX101:/HOME/WSJ # sh Dian
Ni
Ni
Ni
Ni
Ni
Ni

LINUX101:/HOME/WSJ # More Dian
#!/bin/ksh
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"

: '
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
'

2014-02-03-06 added:

Law III:

If false; Then

Statement 1

Statement 2

Statement 3

Statement 4

Fi

LINUX101:/HOME/WSJ # sh Dian
Ni
Ni
Ni
Ni
Ni
Ni

LINUX101:/HOME/WSJ # More Dian
#!/bin/ksh
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"

If false; Then
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
echo "Ni"
Fi

Law four:

: << character #这里的字符可以是数字或者是字符都可以

Statement 1

Statement 2

Statement 3

Statement 4

Character

2014-09-10 Happy teachers ' day, supplemented by Chaosink buddies and Dablelv buddies 2017-09-27:

Law Five:

((0)) && {

Statement 1

Statement 2

Statement 3

}