how to read file from line x to the end of a file in bash

Question

I would like know how I can read each line of a csv file from the second line to the end of file in a bash script.

I know how to read a file in bash:

Answer 1

I would just get a variable.

#!/bin/bash

i=0
while read line
do
    if [ $i != 0 ]; then
      echo -e $line
    fi
    i=$i+1
done < "file.csv"

UPDATE Above will check for the $i variable on every line of csv. So if you have got very large csv file of millions of line it will eat significant amount of CPU cycles, no good for Mother nature.

Following one liner can be used to delete the very first line of CSV file using sed and then output the remaining file to while loop.

sed 1d file.csv | while read d; do echo $d; done

Answer 2

tail -n +2 file.csv

From the man page:

-n, --lines=N
     output the last N lines, instead of the last 10
...

If the first character of N (the number of bytes or lines)  is  a  '+',
print  beginning with the Nth item from the start of each file, other-
wise, print the last N items in the file.

In English this means that:

tail -n 100 prints the last 100 lines

tail -n +100 prints all lines starting from line 100

Answer 3

This will work

i=1
while read line
 do   
   test $i -eq 1 && ((i=i+1)) && continue
   echo -e "$line\n"
done < file.csv

Answer 4

Simple solution with sed:

sed -n '2,$p' <thefile

where 2 is the number of line you wish to read from.

Answer 5

There are many solutions to this. One of my favorite is:

(head -2 > /dev/null; whatever_you_want_to_do) < file.txt

You can also use tail to skip the lines you want:

tail -n +2 file.txt | whatever_you_want_to_do

Answer 6

Depending on what you want to do with your lines: if you want to store each selected line in an array, the best choice is definitely the builtin mapfile:

numberoflinestoskip=1
mapfile -s $numberoflinestoskip -t linesarray < file

will store each line of file file, starting from line 2, in the array linesarray.

help mapfile for more info.

If you don't want to store each line in an array, well, there are other very good answers.

As F. Hauri suggests in a comment, this is only applicable if you need to store the whole file in memory.

Otherwise, you best bet is:

{
    read; # Just a scratch read to get rid (pun!) of the first line
    while read line; do
        echo "$line"
    done
} < file.csv

Notice: there's no subshell involved/needed.