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This article introduces the knowledge of "how to understand the location variables of special variables in Shell programming". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

1. $0 gets the file name of the current script, including the path.

The code is as follows:

# write a test script

Vim test.sh

# the content is as follows

Dirname$0

Basename$0

# execute it

Bash$ (pwd) / test.sh

# the output is as follows

/ home/jane

Test.sh

2. $n gets the nth parameter of the currently executed script, which is the name of the current script. If n is greater than 9, use ${10}

The code is as follows:

Echo'echo'$(seq-s "$" 1 5 | sed's/1/$1/') > test_n.sh

Cattest_n.sh

# the content is as follows

# echo $1 $2 $3 $4 $5

Bashtest_n.sh arg1 agr2 arg3

# output content:

# arg1 agr2 arg3

3. $* get all the parameters of the script

The code is as follows:

Echo'echo $*'> test_*.sh

Cattest_*.sh

# contents are as follows:

# echo $*

Bashtest_*.sh 1 2 3

# output:

# 1 2 3

4. $# get the number of all parameters in the script

The code is as follows:

Echo'echo $#'> test_j.sh

Cattest_j.sh

# contents are as follows:

# echo $#

Bashtest_j.sh 1 2 3

# output:

# 3

This is the end of "how to understand the location variables of special variables in Shell programming". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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