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> awk, Tcl, and Unix shells only have strings, so in a surprising twist, they have no concept of null whatsoever. In shell a variable can be unset, which is di
by jwilk 8y ago
> awk, Tcl, and Unix shells only have strings, so in a surprising twist, they have no concept of null whatsoever.
In shell a variable can be unset, which is different than set to empty string.
- frou_dh 8y agoThis table shows some ways that distinction can be used when expanding a $variable http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02 http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3... Make extensive use of these for maximum job security! /s