A problem caused by mixed shell

An error is reported when a sh is started in debian today, which leads to the formation of this article: when bashshell is used, we have the following scenario: env. sh -- define public variable run1.sh -- define run code run2.sh -- define run code if env. sh...

An error is reported when a sh is started in debian today, which leads to the formation of this article:

 

When using bash shell, we have the following scenarios:

Env. sh -- define public variables

Run1.sh -- define the running code

Run2.sh -- define the running code

 

 

If the content in env. sh changes according to the specific run *. sh, you need to input a variable to env. sh.

Many may adopt this method,

 

Scenario simulation:

Env. sh:

View plaincopy to clipboardprint? #! /Bin/sh
Echo $1
#! /Bin/sh
Echo $1

 

Run1.sh:
View plaincopy to clipboardprint? #! /Bin/sh
 
CURRENT_PATH = 'core'
 
Echo $ {CURRENT_PATH}
 
./Home/admin/tmp/madding. lip/env. sh $ CURRENT_PATH
 
Echo "invoke $ CURRENT_PATH-service $1"
 
If ["$1" = "stop"]; then
Echo "'date': stop --------------------------------"
Echo "remove $ shutdownFile"
Elif ["$1" = "debug"]; then
Echo "'date': debug --------------------------------"
Fi
#! /Bin/sh

CURRENT_PATH = 'core'

Echo $ {CURRENT_PATH}

./Home/admin/tmp/madding. lip/env. sh $ CURRENT_PATH

Echo "invoke $ CURRENT_PATH-service $1"

If ["$1" = "stop"]; then
Echo "'date': stop --------------------------------"
Echo "remove $ shutdownFile"
Elif ["$1" = "debug"]; then
Echo "'date': debug --------------------------------"
Fi

 

 

Run the following command:

Sh run. sh start

 

Result:

On redhat 5.3:

Core
Core
Invoke core-service

 

Debian 6:

Core

Start

Invoke core-service

 

 

 

Analysis:

 

 

The problem is:

View plaincopy to clipboardprint ?. /Home/admin/tmp/madding. lip/env. sh $ CURRENT_PATH
./Home/admin/tmp/madding. lip/env. sh $ CURRENT_PATH

 

Fundamentals:

Default debian:

View plaincopy to clipboardprint? Madding @ wmmad :~ $ Which sh
/Bin/sh
Madding @ wmmad :~ $ Ls-l/bin/sh
Lrwxrwxrwx 1 root 4 Jun 6 05:49/bin/sh-> dash
Madding @ wmmad :~ $ Which sh
/Bin/sh
Madding @ wmmad :~ $ Ls-l/bin/sh
Lrwxrwxrwx 1 root 4 Jun 6 05:49/bin/sh-> dash

Redhat default sh usage:

View plaincopy to clipboardprint? [Admin @ **** ~] $ Which sh
/Bin/sh
[Admin @ **** ~] $ Ls-l/bin/sh
Lrwxrwxrwx 1 root 4-Nov 16 2010/bin/sh-> bash
[Admin @ **** ~] $ Which sh
/Bin/sh
[Admin @ **** ~] $ Ls-l/bin/sh
Lrwxrwxrwx 1 root 4-Nov 16 2010/bin/sh-> bash

 

 

Handling suggestion:

1. shell should be written in a compatible way as much as possible, so it is more portable.

2. if the shell is explicitly used, it should be indicated in the header as much as possible, so that the specific shell can be identified during the./method execution.

3. if you use a specific shell Step-by-step method for execution, it is recommended to specify the parser for shell step, such as dash xx. sh or bash xx. sh.

Author "madding. lip"