Delete First line of a file

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

[user@work ~]$ 

Coming back to sed, try:

printf '%s\n\n' "$(sed '1d' file.txt)" > file.txt

or perhaps

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

To avoid side effects.


The reason file.txt is empty after that command is the order in which the shell does things. The first thing that happens with that line is the redirection. The file "file.txt" is opened and truncated to 0 bytes. After that the sed command runs, but at the point the file is already empty.

There are a few options, most involve writing to a temporary file.

sed '1d' file.txt > tmpfile; mv tmpfile file.txt # POSIX
sed -i '1d' file.txt # GNU sed only, creates a temporary file

perl -ip -e '$_ = undef if $. == 1' file.txt # also creates a temporary file

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