Delete First line of a file

Also take a look at sponge from
moreutils. sponge soaks in data from
standard input until standard input’s writing end closes before writing to a
file. It is used like so:

sed '1d' file.txt | sponge file.txt

ex can be used for true in-place editing that does not involve a temp file

ex -c ':1d' -c ':wq' file.txt

An alternative very lightweight option is just to ‘tail’ everything but the first line (this can be an easy way to remove file headers generally):

# -n +2 : start at line 2 of the file.
tail -n +2 file.txt > file.stdout

Following @Evan Teitelman, you can:

tail -n +2 file.txt | sponge file.txt

To avoid a temporary file. Another option might be:

echo "$(tail -n +2 file.txt)" > file.txt

And so forth. Testing last one:

[user@work ~]$ cat file.txt
line 1
line 2
line 3
line 4
line 5

[user@work ~]$ echo "$(tail -n +2 file.txt)" > file.txt
[user@work ~]$ cat file.txt
line 2
line 3
line 4
line 5
[user@work ~]$ 

Oops we lost a newline (per @1_CR comment below), try instead:

printf "%snn" "$(tail -n +2 file.txt)" > file.txt

[user@work ~]$ cat file.txt
line 1
line 2
line 3
line 4
line 5

[user@work ~]$ printf '%snn' "$(tail -n +2 file.txt)" > file.txt
[user@work ~]$ cat file.txt
line 2
line 3
line 4
line 5  

[user@work ~]$ 

Coming back to sed, try:

printf '%snn' "$(sed '1d' file.txt)" > file.txt

or perhaps

echo -e "$(sed '1d' file.txt)n" > file.txt

To avoid side effects.

This command will remove 1 line and save as “file.txt”.

sed '1d' file.txt  > /tmp/file.txt && mv /tmp/file.txt file.txt || rm -f /tmp/file.txt

This topic is interest, so I test the benchmark in 3 ways:

1. sed '1d' d.txt > tmp.txt
2. tail -n +2 d.txt > tmp.txt
3. sed -i '1d' d.txt

Note that target d.txt is 5.4GB file

Get the result :

---

run 1 : sed '1d' d.txt > r1.txt
14s
run 2 : tail -n +2 d.txt > r2.txt
20s
run 3 : sed -i '1d' d.txt
88s

---

Conclusion : It seems below be the quickest way:

sed '1d' file.txt > tmpfile; mv tmpfile file.txt

To delete a particular line in file:

1. Delete first line

   sed '1d' file
   

2. Delete first and third line

   sed '1d3d' file
   

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
   

You can use Vim in Ex mode:

ex -s -c '1d|x' file.txt

1. 1 find first line

2. d delete

3. x save and close

The shortest and simplest way to delete the first line from a file using sed is:

$ sed -i -n -e '2,$p' file.txt

Could use vim to do this:

vim -u NONE +'1d' +wq! /tmp/test.txt

You can try this:

awk 'NR>1 {print}' file.txt > file1.txt