From https://unix.stackexchange.com/a/378549/674
tmp=${string//"$separator"/$'\2'} What does $ in $'\2' mean?
Is $'\2' a parameter expansion?
Thanks.
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1 Answer
This is ANSI-C Quoting:
Words of the form
$'string'are treated specially. The word expands tostring, with backslash-escaped characters replaced as specified by the ANSI C standard.
$'\2' is expanded to the eight-bit character whose value is the octal value 2. In the answer you refer to, this character is used as a field separator.
- Thanks. In C language, how is
$\2specified instead?Tim– Tim2017-08-01 14:24:07 +00:00Commented Aug 1, 2017 at 14:24 -
$introduces the string in Bash, it has no special meaning in C; if you wanted to store the string$\2in C, you’d just escape the backslash,$\\2.Stephen Kitt– Stephen Kitt2017-08-01 14:28:31 +00:00Commented Aug 1, 2017 at 14:28 - Thanks. In C, how is the octal value 2 specified? Is it
0x2? Is there a similar metacharacter in C to$in Bash?Tim– Tim2017-08-01 14:30:30 +00:00Commented Aug 1, 2017 at 14:30 - In C, in a numeric context you just use a leading 0 for an octal value, so 010 is 8; in a string context with a backslash, values are treated as octal anyway. There’s no need for a
$-style metacharacter, backslashes are interpreted in this way in all C strings: you’d just write"\2".Stephen Kitt– Stephen Kitt2017-08-01 14:42:03 +00:00Commented Aug 1, 2017 at 14:42