Quickly clear text files in linux and clear linux text files

Quickly clear text files in linux and clear linux text files
1. [root @ desktop huage] #:> filename
: Is a placeholder and does not generate any input
 
2. [root @ desktop huage] #> filename
No output is generated.
 
3. [root @ desktop huage] # echo ""> filename
A blank row is displayed. The file size is 1 byte.
 
4. [root @ desktop huage] # echo> filename
A blank row is displayed. The file size is 1 byte.
 
5. [root @ desktop log] # cat/dev/null> filename
File does not produce any output
How does one clear File Content in Linux?

Opened and deleted with vi
Capture cat/dev/null> filename

Linux Command to clear a text file?

# Rm filename.txt; touch filename.txt

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A command? Another thought