多行变一行

1. xargs
   xargs < myfile

2. variable
   a=$(cat myfile); echo $a

3. tr
   tr -s ‘\n’ ’ ’ < myfile

4. sed
   sed -n ‘1h;1H;${g; s/\n//g; p;}’ myfile
   sed ‘:a; N; s/\n//; ta;’ myfile

5. awk
   awk ‘{printf(“%s “, $0);}END{print}’ myfile
   awk ‘BEGIN{RS=EOF}{gsub(/\n/, ” “); print}’ myfile

6. paste -d分隔符 -s合并
   paste -d”” -s - < myfile

7. pr -s分隔符 -50每行打印50个域 -t取消页眉
   pr -50t -s” ” myfile

# 获取本地实例监听名
cat listener.ora | awk 'BEGIN{RS=EOF} /=/{gsub(/\n/, "");print}' | awk -v sid=$ORACLE_SID -F= '$1~/sid/{print $1}' | sed 's/SID_LIST_//'