One-Day Study Shell:Part 2 Shell Path Parameter

雨点打透心脏的1/2处 2022-10-09 12:17 21阅读 0赞

### One-Day Study Shel:Part 2 Shell Path Parameter ###

*  Shell path parameter

# Shell path parameter #

*  **Get parameter from shell `$n`**  
    n is a number  
    n=1 (The first parameter to execute shell )  
    n=2 (The second parameter to execute shell )

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2tla2VfTWVtb3J5_size_16_color_FFFFFF_t_70_pic_center]

<table> 
 <thead> 
  <tr> 
   <th>parameter</th> 
   <th>description</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td><code>$#</code></td> 
   <td>The number of the parameters passed to the shell</td> 
  </tr> 
  <tr> 
   <td><code>$*</code></td> 
   <td>Display all the parameters passed to the shell with a single string</td> 
  </tr> 
  <tr> 
   <td>``$$</td> 
   <td>Current process id of the running shell</td> 
  </tr> 
  <tr> 
   <td><code>$!</code></td> 
   <td>id of the last process running in the background</td> 
  </tr> 
  <tr> 
   <td><code>$@</code></td> 
   <td>Same with <code>$*</code>, use with<code>""</code></td> 
  </tr> 
  <tr> 
   <td><code>$-</code></td> 
   <td>Display the current options used by the shell</td> 
  </tr> 
  <tr> 
   <td><code>$?</code></td> 
   <td>Display the exit status of the last command. <code>0</code> means no error</td> 
  </tr> 
 </tbody> 
</table>

#!/bin/bash
    # author:keke
    
    echo "Shell pass parameter~"
    echo "Executed file name: $0"
    echo "The first parameter is: $1"
    echo "The second parameter is: $2"
    echo "The third parameter is: $3"
    
    echo "The number of the parameters: $#"
    echo "Use \$* to Display all the parameters passed to the shell with a single string: $*"
    echo "Use \$@ to Display all the parameters passed to the shell with a single string: $@"
    
    echo "See difference between --\$*-- and --\$--"
    echo "Display with --\$*--"
    for i in "$*";do
        echo $i
    done
    
    echo "Display with --\$@--"
    for i in "$@";do
        echo $i
    done

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2tla2VfTWVtb3J5_size_16_color_FFFFFF_t_70_pic_center 1]

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