双引号

双引号保留除 " 终结符,$ 扩展,`命令替换和任何这些字符的\转义(以及换行符)之外的所有字符。请注意,除非后跟特殊字符,否则将保留文字\

一般转义:

$ printf "\"quoted string\"\\n"
"quoted string"
$ printf "\`\`quoted string''\n"
``quoted string''
$ printf "four\\\\nthree\\\ntwo\\none\n"
four\nthree\ntwo
one
$ echo "var=\`echo \$var\`"
var=`echo $var`
$ echo "var=\$(echo \$var)"
var=$(echo $var)

可变扩展:

$ var=variable echo "$var \$var \\$var \\\$var"
variable $var \variable \$var

命令替换:

$ var=variable echo "var=`echo $var`"
var=variable
$ var=variable echo "var=$(echo $var)"
var=variable

删除换行符:

$ echo "multi\
> -line"
multi-line