1、sed -n '$p' $file打印尾行
2、sed -i '$d' $file删除尾行
3、例如a.sh
#!/bin/sh
file=$1
if [[ -z $1 ]];then
echo Usage $0 file;
exit 0;
fi
while [[ -z $tt ]];do
tt=$(sed -n '$p' $file)
if [[ -z $tt ]];then
sed -i '$d' $file
fi
done
sed -n '$p' $file
cat file|grep -v "^$"|tail -n 1