使用sed将2个变量与正斜杠一起替换到一个变量位置

Question

i am trying to replace 2 variables with / in-between 2 variables but its giving sed expression -e error

 sed 's/'$presentnetwork'/'$netmask\/$subnet'/g' -i /etc/snmp/snmpd.conf

How to put the / and also substitute a variable using sed even if i try to put only one variable it is also not working

 sed 's/'$presentnetwork'/'$netmask\/'/g' -i /etc/snmp/snmpd.conf

Is it possible to use escape sequence and variable in the same sed command?

Answer 1

You need to wrap it with double quotes " :

sed "s/$presentnetwork/$netmask\//g" -i /etc/snmp/snmpd.conf
#   ^                              ^

Example:

$ cat a.html 
hello
$ a=hello
$ b=good
$ c=bye
$ sed "s/$a/$b\/$c/g" -i a.html 
$ cat a.html 
good/bye

Answer 2

sed不仅限于/作为分隔符，您还可以使用其他一些字符来使转义更加容易（如果您知道该字符不能成为变量的一部分）：

 sed "s_$presentnetwork_$netmask/_g" -i /etc/snmp/snmpd.conf