How do I remove the last two lines in Unix?

How do I remove the last few 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 I remove the last field in Unix?

Create a macro named “q” qq , that goes to the back of the current line $ , then goes back to the last space F (capital F, followed by literal SPACE) then delete from current position through end of line D go down to the next line j and stop macro recording with q .

How do I remove the last 10 lines in Linux?

Remove the Last N Lines of a File in Linux

1. awk.
2. head.
3. sed.
4. tac.
5. wc.

How do you remove a line 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 the first 10 lines in Unix?

Remove first N lines of a file in place in unix command line

1. Both sed -i and gawk v4.1 -i -inplace options are basically creating temp file behind the scenes. IMO sed should be the faster than tail and awk . – …
2. tail is multiple times faster for this task, than sed or awk . (

How do you remove multiple lines in Unix?

Deleting Multiple Lines

1. Press the Esc key to go to normal mode.
2. Place the cursor on the first line you want to delete.
3. Type 5dd and hit Enter to delete the next five lines.

How do you cut the first two fields in UNIX?

Explanation:

1. cut : invoke the cut command.
2. -d ” ” : use a single space as the delimiter ( cut uses TAB by default)
3. -f : specify fields to keep.
4. 3- : all the fields starting with field 3.
5. input_filename : use this file as the input.
6. > output_filename : write the output to this file.

What is the use of awk in Linux?

Awk is a utility that enables a programmer to write tiny but effective programs in the form of statements that define text patterns that are to be searched for in each line of a document and the action that is to be taken when a match is found within a line. Awk is mostly used for pattern scanning and processing.

How do I change my awk delimiter?

Just put your desired field separator with the -F option in the AWK command and the column number you want to print segregated as per your mentioned field separator. AWK works as a text interpreter that goes linewise for the whole document and that goes fieldwise for each line.

How do I remove the first line in Unix?

Using the sed Command

Removing the first line from an input file using the sed command is pretty straightforward. The sed command in the example above isn’t hard to understand. The parameter ‘1d’ tells the sed command to apply the ‘d’ (delete) action on line number ‘1’.

How do I clear history in Linux?

Removing history

If you want to delete a particular command, enter history -d <line number> . To clear the entire contents of the history file, execute history -c . The history file is stored in a file that you can modify, as well.

How do I delete multiple lines in Linux history?

You can use history -d offset builtin to delete a specific line from the current shell’s history, or history -c to clear the whole history. It’s not really practical if you want to remove a range of lines, since it only takes one offset as an argument, but you could wrap it in a function with a loop.

How do I remove a grep line?

Use the grep command to delete the line containing the specified string. Grep command, we use it more to match the specified string in the text file. Since it can be matched, it can also be excluded, you need to use the grep -v option.

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 you delete a line in Linux?

To delete a line, follow the steps below:

1. First, bring your cursor to the line you want to delete.
2. Press the “Esc” key to change the mode.
3. Now type, “:d”, and press “Enter” to delete the line or quickly press “dd”.