Which of the following commands will NOT update the modify timestamp on the file /tmp/myfile.txt?
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A. B. C. D. E.A
The command that will NOT update the modify timestamp on the file /tmp/myfile.txt is option D: echo -n "Hello" >>/tmp/myfile.txt.
Explanation:
In Linux, there are three timestamps associated with each file: the access time (atime), the modify time (mtime), and the change time (ctime). The atime is the time when the file was last accessed, the mtime is the time when the file was last modified, and the ctime is the time when the file's metadata was last changed.
Option A: file /tmp/myfile.txt does not modify the file in any way, so it will not update any of the timestamps.
Option B: echo "Hello" >>/tmp/myfile.txt appends the string "Hello" to the end of the file, which modifies the file and updates its mtime and ctime.
Option C: sed -ie "s/1/2/" /tmp/myfile.txt modifies the contents of the file by replacing the first occurrence of "1" with "2" and updates the mtime and ctime of the file.
Option D: echo -n "Hello" >>/tmp/myfile.txt appends the string "Hello" to the end of the file without adding a newline character, which modifies the file and updates its mtime and ctime.
Option E: touch /tmp/myfile.txt updates the mtime and atime of the file to the current time, and if the file does not exist, it creates an empty file with the specified name.