Do you have a method to quickly remove the first line of a file in bash shell ? I mean using sed or stuff like that.
3 Answers
One-liners in reverse order of length, portable unless noted.
sed (needs GNU sed for -i):
sed -i 1d file
ed (needs e.g. bash for $'...' expansion and here string):
ed file <<< $'1d\nw\nq'
awk:
awk NR\>1 infile > outfile
tail:
tail -n +2 infile > outfile
read + cat:
(read x; cat > outfile) < infile
bash built-ins:
while IFS= read -r; do ((i++)) && printf %s\\n "$REPLY" >> outfile; done < infile
$ tail -n +2 <<< $'1\n2\n3'
2
3
Using dd
fn="The-BIG-FILE.txt"
fll=$(( $(head -n 1 $fn | wc -c) + 1))
dd if="$fn" of="${fn}.out" bs=1M iflags=skip_bytes skip=$fll
echo "Files differ by $(( $(find $fn* -printf "%s - \n" ; echo "0") )) bytes. First line of $fn is $fll bytes."
Add any iflags= and oflags= you might need - with commas separating them.
