CODEWITHSUNDEEP
linuxbashunixsh
user3905438
user3905438

Reputation: 451

How to display all the lines from the nth line of a file in unix

I want to display all the lines starting from the nth line. Say, print the third line of a file and all the following lines until end of file. Is there a command for that?

Upvotes: 44

Views: 65547

Answers (6)

Alain Collins
Alain Collins

Reputation: 16362

You can use sed:

sed -n '3,$p' file

This selects line 3 to the end and prints it.

Upvotes: 16

paxdiablo
paxdiablo

Reputation: 881163

The awk command can do this by only printing lines to the NR record number is three or more:

awk 'NR>=3' input_file_name

You can also pass the value into awk using a variable if need be:

awk -v n=3 'NR>=n' input_file_name

(and you can use -v n=${num} to use an environment variable as well).

There are many other tools you can use to do the same job, tail, sed and perl among them or, since this is a programming Q&A site, just roll your own:

#include <stdio.h>

int main (void) {
    // Need character and # of newlines to skip.

    int ch, newlines = 2;

    // Loop until EOF or first lines skipped, exit on EOF.

    while ((ch = getchar()) != EOF)
        if ((ch == '\n') && (--newlines == 0))
            break;

    if (ch == EOF)
        return 0;

    // Now just echo all other characters, then return.

    while ((ch = getchar()) != EOF)
        putchar (ch);

    return 0;
}

Now you wouldn't normally write your own filter program for this but, since you asked for the shortest command, you could use that source code to create an executable called x to do it:

x <input_file_name

You'd be hard-pressed finding a shorter command than that. Of course, assuming you're in a UNIXy environment (specifically, bash), you could also just:

alias x awk 'NR>=3'

:-)

Upvotes: 4

John B
John B

Reputation: 3646

You can use awk like this:

awk 'BEGIN{n=5}NR<=n{next}1' file
  • BEGIN{n=5} - before file processing starts, sets n to the number of lines to skip (5).
  • NR<=n{next} - skips processing if the line number is less than or equal to n.
  • 1 - shorthand for print everything else.

Upvotes: 5

Juan Diego Godoy Robles
Juan Diego Godoy Robles

Reputation: 14945

To show from 5th line:

awk 'NR>4' file

Upvotes: 15

Nikolaus Gradwohl
Nikolaus Gradwohl

Reputation: 20124

you can use tail

excerpt from the manpage:

   -n, --lines=K
         output the last K lines, instead of the last 10; or use -n +K to
         output lines starting with the Kth

for example 

tail -n +10 file

outputs the files content starting with the 10th line

Upvotes: 69

Beta
Beta

Reputation: 99094

Print, but delete lines 1 through 2:

sed '1,2d' filename

Upvotes: 5

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