使用Shell脚本搜索和替换变量字符串

Question

I am in dilemma about how could I search and replace a particular character in a variable of a shell script.

eg I have a condition where I need to pass '~' to the java program but I should pass it as '/~' to avoid it being intercepted as $HOME. I have a shell variable eg $1 = '.-~' and I am passing it directly to the Java program as an argument. So how could I modify this variable in such a way that it searches for '~' and if it finds then changes $1 = '.-/~' so as to avoid the error in Java program.

I tried $(1//~//~) but it gives me an error.

Also this gave me an error.

sed 's#~#/#g' <<< $x;

Answer 1

To replace a string in a shell variable, you can use var modifiers like this:

${YOURVAR/The string you want to search/The string you want to replace to}

By example:

${HOME/~/world} -> "hello ~" become "hello world"

Answer 2

For both your attempts you have two options:

"${1//\~//~}"  ## ~ in pattern needs to be backslash quoted.

And

sed 's#~#/~#g' <<< "$x"  ## $x should be placed in double quotes to prevent other word splitting or expansions. And you probably forgot ~.

Other versions to replace with \\ instead:

"${1//\~/\\~}"
sed 's#~#\\~#g' <<< "$x"