linux - 仅当文件尚未在文件中时才将行添加到文件中

Question

我想添加以下行：

nohup java -jar /mnt/fusion/nfs/labStats/LabInfoAutoLog.jar > /dev/null &

/etc/rc.d/rc.local如果文件不存在，则到文件末尾。

我怎样才能从linux命令行做到这一点？我假设grep或sed会工作，但我对任何一个都不够熟悉，无法让它工作。现在我使用echo，但这只是一遍又一遍地添加它。

Answer 1

假设您希望它在文件末尾：

LINE="nohup java -jar /mnt/fusion/nfs/labStats/LabInfoAutoLog.jar > /dev/null &"
FILE=/etc/rc.d/rc.local
grep -q "$LINE" "$FILE" || echo "$LINE" >> "$FILE"

Answer 2

one option is two steps:

grep -q "yourline" /path/file||sed -i '/..place../ a \the line' file

also possible to do with awk,

save all lines in array, during saving if the line was found, exit. otherwise, add the line in END{} block to the right place.

P.S. You didn't tell in the file, where to add that line.