Question

我无法正确获取此命令的语法...我需要更改变量包含路径的文件中的变量。

sessionFolderName=/session_`date '+%y%m%d'`_`date '+%H%M'`

sed "s/sessionFolder=.*/sessionFolder=/"$sessionFolder /home/pi/scripts/settings/settings.sh > tmp
mv tmp /home/pi/scripts/settings/settings.sh

但结果是：

sed：-e表达式＃1，字符35：未知选项`s＆＃39;

Answer 1

问题在于变量开头的/字符。这会中断sed语法：

[root@ ~]# sed "s/sessionFolder=.*/${sessionFolderName}/" text
sed: -e expression #1, char 21: unknown option to `s'
[root@ ~]# echo $sessionFolderName
/session_170824_0942

如果你使用双反斜杠 - \\ 来逃避它，它可以工作：

[root@ ~]# sed "s/sessionFolder=.*/sessionFolder=\\${sessionFolderName}/" text
sessionFolder=/session_170824_0942

Answer 2

# You don't need to (and in your case, should not) invoke date command twice.
# Try running following in bash to see the problem.
#     $ echo $(date '+%s')_$(sleep 1)_$(date '+%s')
# On a different note, it's better to use $(...) instead of backticks.
sessionFolderName="/session_$(date '+%y%m%d_%H%M')"

# You can use several other separators in sed.
#  e.g. :, ;, @, #, _ and even a space
sed "s:sessionFolder=.*:sessionFolder=${sessionFolder}:" /home/pi/scripts/settings/settings.sh > tmp
mv tmp /home/pi/scripts/settings/settings.sh

Refer to this关于使用$()而不是反引号

Answer 3

1）您需要转义输入中的/

2）修改sed命令的格式，如下所示

sessionFolderName=\\/session_`date '+%y%m%d'`_`date '+%H%M'`

sed "s/sessionFolder=.*/sessionFolder="$sessionFolderName"/"  /home/pi/scripts/settings/settings.sh > tmp

包含变量不起作用的sed命令

3 个答案: