As a rule of thumb, prefer to avoid using anything requiring eval when you have another way. + echo be aware that depending on the context where you use such structure it may have unwanted side-effect. + echo for some reason you really need to affect the tilde to the $x variable without expansion, and be able to expand it at the echo command, you must proceed in two times to force two expansions of the $x variable to occur: x='~/someDirectory' + echo you can also make the expansion occur on the echo command-line as long as it can happen before parameter expansion: x='someDirectory' A thing often missed is that in shell commands you don't have to quote the whole string, so you can make the expansion happen right during the variable assignment: set -o x=~/'someDirectory' Processing continues, tilde expansion having already been processed the ~ character remains as-is.īy using the quotes while assigning the $x, you were explicitly requesting to not expand the tilde and treat it like a normal character.The shell attempts a parameter expansion on echo $x, $x is found and expanded and the command-line becomes echo ~/someDirectory.The shell attempts a tilde expansion on echo $x, there is no tilde to be found, so it proceeds.The only point which interests us here is the first one: as you can see tilde expansion is processed before parameter expansion: Quote removal (see Quote Removal) shall always be performed last. Pathname expansion (see Pathname Expansion) shall be performed, unless set -f is in effect. See item 5 in Token Recognition.įield splitting (see Field Splitting) shall be performed on the portions of the fields generated by step 1, unless IFS is null.

Tilde expansion (see Tilde Expansion), parameter expansion (see Parameter Expansion), command substitution (see Command Substitution),Īnd arithmetic expansion (see Arithmetic Expansion) shall be The POSIX standard imposes word expansion to be done in the following order (emphasize is mine):

How to make tilde in linux