Quick Answer: How do I remove a line from a file in Unix?

To Remove the lines from the source file itself, use the -i option with sed command. If you dont wish to delete the lines from the original source file you can redirect the output of the sed command to another file.

How do I remove lines from a file?

Use del to delete a line from a file where its position is known {#use-del)

  1. a_file = open(“sample.txt”, “r”) get list of lines.
  2. lines = a_file. readlines()
  3. a_file.
  4. del lines[1] delete lines.
  5. new_file = open(“sample.txt”, “w+”) write to file without line.
  6. for line in lines:
  7. new_file. write(line)
  8. new_file.

How do I remove the first line of a text file in Unix?

To delete a charecter in a line

  1. Delete First two charters in lin sed ‘s/^..//’ file.
  2. Delete last two chrecters in line sed ‘s/..$//’ file.
  3. Delete blank line sed ‘/^$/d’ file.

How do you delete one line from a file in Linux?

You can use the “stream editor for filtering and transforming text” sed. Here, -i means edit the file inplace. d is the command to “delete the pattern space; immediately start next cycle”.

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How do you replace a line in a file using Python?

Replace a Line in a File in Python

  1. Use the for Loop Along With the replace() Function to Replace a Line in a File in Python.
  2. Create a New File With the Refreshed Contents and Replace the Original File in Python.
  3. Use the fileinput.input() Function for Replacing the Text in a Line in Python.

How do I remove the first line from a file?

Then, we’ll test each solution on our big input file to remove the first line.

To benchmark their performance, we’ll use the time command:

  1. The sed solution: time sed ‘1d’ big. txt > /dev/null.
  2. The awk solution: time awk ‘NR>1’ big. txt > /dev/null.
  3. The tail solution: time tail -n +2 big. txt > /dev/null.

How do you delete the first and last line in Unix?

How it works :

  1. -i option edit the file itself. You could also remove that option and redirect the output to a new file or another command if you want.
  2. 1d deletes the first line ( 1 to only act on the first line, d to delete it)
  3. $d deletes the last line ( $ to only act on the last line, d to delete it)

What is NR in awk command?

NR is a AWK built-in variable and it denotes number of records being processed. Usage : NR can be used in action block represents number of line being processed and if it is used in END it can print number of lines totally processed. Example : Using NR to print line number in a file using AWK.

How do I remove the last line in Unix?

6 Answers

  1. Use sed -i ‘$d’ <file> to edit file in place. – …
  2. What would be for deleting the last n lines, where n is any integer number? – …
  3. @JoshuaSalazar for i in {1..N}; do sed -i ‘$d’ <file>; done dont forget to replace N – ghilesZ Oct 21 ’20 at 13:23.
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How do I remove the last 10 lines in Unix?

It’s a little roundabout, but I think it’s easy to follow.

  1. Count up the number of lines in the main file.
  2. Subtract the number of lines you want to remove from the count.
  3. Print out the number of lines you want to keep and store in a temp file.
  4. Replace the main file with the temp file.
  5. Remove the temp file.

How do you delete a file in Linux?

How to Remove Files

  1. To delete a single file, use the rm or unlink command followed by the file name: unlink filename rm filename. …
  2. To delete multiple files at once, use the rm command followed by the file names separated by space. …
  3. Use the rm with the -i option to confirm each file before deleting it: rm -i filename(s)
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