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something wrong when overwriting file [duplicate]

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.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ margin-bottom:0;
}

0

This question already has an answer here:

• 
  What are the shell's control and redirection operators?
  
  3 answers
  
  


• 
  Do redirection operators always open file descriptors in parallel?
  
  2 answers
  
  

I was trying to delete the last line and overwrite the file. But I failed for some reason. I could write the modified text to another file though.

$cat > file.txt

a

b

c



$set "$d" file.txt > file2.txt

$cat file2.txt

a

b

however when I enter this：

$set "$d" file.txt > file.txt

$cat file.txt

It shows nothing meaning file.txt is empty now.
I wonder why this happens?

shell-script

share|improve this question

asked 56 mins ago

Jack ChenJack Chen

1

New contributor

Jack Chen is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

marked as duplicate by Scott, icarus, Community♦ 10 mins ago

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  See Warning regarding ‘‘>’’.
  
  – Scott
  39 mins ago
  

  
  
  
  

add a comment | 

0

This question already has an answer here:

• 
  What are the shell's control and redirection operators?
  
  3 answers
  
  


• 
  Do redirection operators always open file descriptors in parallel?
  
  2 answers
  
  

I was trying to delete the last line and overwrite the file. But I failed for some reason. I could write the modified text to another file though.

$cat > file.txt

a

b

c



$set "$d" file.txt > file2.txt

$cat file2.txt

a

b

however when I enter this：

$set "$d" file.txt > file.txt

$cat file.txt

It shows nothing meaning file.txt is empty now.
I wonder why this happens?

shell-script

share|improve this question

asked 56 mins ago

Jack ChenJack Chen

1

New contributor

Jack Chen is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

marked as duplicate by Scott, icarus, Community♦ 10 mins ago

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  See Warning regarding ‘‘>’’.
  
  – Scott
  39 mins ago
  

  
  
  
  

add a comment | 

This question already has an answer here:

• 
  What are the shell's control and redirection operators?
  
  3 answers
  
  


• 
  Do redirection operators always open file descriptors in parallel?
  
  2 answers
  
  

I was trying to delete the last line and overwrite the file. But I failed for some reason. I could write the modified text to another file though.

$cat > file.txt

a

b

c



$set "$d" file.txt > file2.txt

$cat file2.txt

a

b

however when I enter this：

$set "$d" file.txt > file.txt

$cat file.txt

It shows nothing meaning file.txt is empty now.
I wonder why this happens?

shell-script

share|improve this question

asked 56 mins ago

Jack ChenJack Chen

1

New contributor

Jack Chen is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$cat > file.txt

a

b

c



$set "$d" file.txt > file2.txt

$cat file2.txt

a

b

$set "$d" file.txt > file.txt

$cat file.txt

share|improve this question

asked 56 mins ago

Jack ChenJack Chen

1

New contributor

Jack Chen is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

asked 56 mins ago

Jack ChenJack Chen

1

New contributor

Jack Chen is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 56 mins ago

Jack ChenJack Chen

1

New contributor

Jack Chen is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 56 mins ago

Jack ChenJack Chen

1