In November 2021 I filed a feature request for the fish shell to add underscore as a thousand separator in numbers. My feature request has been implemented and is available in fish 3.5.0, released 16 June 2022.
The fish shell supports mathematical operations using the
edward@x1c9 ~> math 2_000 + 22 2022 edward@x1c9 ~>
// A decimal integer literal with its digits grouped per thousand: 1_000_000_000_000 // A decimal literal with its digits grouped per thousand: 1_000_000.220_720 // A binary integer literal with its bits grouped per octet: 0b01010110_00111000 // A binary integer literal with its bits grouped per nibble: 0b0101_0110_0011_1000 // A hexadecimal integer literal with its digits grouped by byte: 0x40_76_38_6A_73 // A BigInt literal with its digits grouped per thousand: 4_642_473_943_484_686_707n
Programming languages are gradually adding a number separator to their syntax, I think Perl was the first. Most are languages use underscore, but C++ 14 uses an apostrophe for the number separator.