not sure if this is what you meant:
ls, cp -a tester* $out/share/icons gave:
[anna@sommerfugl:~]$ sudo nixos-rebuild switch --show-trace
building Nix…
building the system configuration…
these derivations will be built:
/nix/store/nqcis179i9zqx60pyjwpjgd9vg87wa68-tester-icons-2020-08-09.drv
/nix/store/ms50zii9f34bsmgvs9d9b6m7sxyvpskv-system-path.drv
/nix/store/06b4sk0wskgzv5pryjgpmwf5yx0jmpqk-unit-accounts-daemon.service.drv
/nix/store/08plzzd1dd73dck7apzg67h3nzajbm87-unit-polkit.service.drv
/nix/store/45i1h0frx12dx7lyxjqdxmd1jm13l8wm-dbus-1.drv
/nix/store/pdwr81fjblcgspqxmibh2fw256kch2cx-unit-dbus.service.drv
/nix/store/xd0ylkissfm1arq2xa92ll3jddajg6lj-unit-systemd-fsck-.service.drv
/nix/store/rzvnfkjypznkxmr1z2clgwzdcvhz6452-system-units.drv
/nix/store/z5jqw0n1v4557zpbswsvhpwssw9irs7x-unit-dbus.service.drv
/nix/store/z60vlv68g0nyzy48kxi6s93k7mny3hcn-user-units.drv
/nix/store/j8pkicljfjvyg76cndr3hkahajs1jvla-etc.drv
/nix/store/2xhjqwlhp8698nh0v67wh8w2adg4w2sg-nixos-system-sommerfugl-20.09.1500.edb26126d98.drv
building ‘/nix/store/nqcis179i9zqx60pyjwpjgd9vg87wa68-tester-icons-2020-08-09.drv’…
unpacking sources
unpacking source archive /nix/store/9iri7fmnsrdm0b5gh5yfld2vbj0zlbs0-tester
source root is tester
patching sources
configuring
no configure script, doing nothing
building
no Makefile, doing nothing
glibPreInstallPhase
installing
/nix/store/333six1faw9bhccsx9qw5718k6b1wiq2-stdenv-linux/setup: line 1303: ls,: command not found
builder for ‘/nix/store/nqcis179i9zqx60pyjwpjgd9vg87wa68-tester-icons-2020-08-09.drv’ failed with exit code 127
cannot build derivation ‘/nix/store/ms50zii9f34bsmgvs9d9b6m7sxyvpskv-system-path.drv’: 1 dependencies couldn’t be built
cannot build derivation ‘/nix/store/2xhjqwlhp8698nh0v67wh8w2adg4w2sg-nixos-system-sommerfugl-20.09.1500.edb26126d98.drv’: 1 dependencies couldn’t be built
error: build of ‘/nix/store/2xhjqwlhp8698nh0v67wh8w2adg4w2sg-nixos-system-sommerfugl-20.09.1500.edb26126d98.drv’ failed
not sure if this is what you meant:
ls cp -a tester* $out/share/icons gave:
> [anna@sommerfugl:~]$ sudo nixos-rebuild switch --show-trace
> building Nix...
> building the system configuration...
> these derivations will be built:
> /nix/store/v2cfkd90jqp4j338xn8g243j6vmcqaw1-tester-icons-2020-08-09.drv
> /nix/store/n2xaz27wgkmbdc618ihvjrg1xs68c6jx-system-path.drv
> /nix/store/q55kr4nkqvlxj6as64kdxllgdx0hip5m-dbus-1.drv
> /nix/store/hqbw0b2zmc7rabgjcg4fs2hz2hwcs2q9-unit-dbus.service.drv
> /nix/store/8wy5wl12gn8ip39z4gxaw4jbiciifgzx-user-units.drv
> /nix/store/dsw3zfx51znz1d1263fvwa0jz07rh8pv-unit-dbus.service.drv
> /nix/store/l2y4pq2f5snf8f652s7nlmdb6giika0x-unit-accounts-daemon.service.drv
> /nix/store/mh070vp73712dks4i2arzywiia6ix057-unit-systemd-fsck-.service.drv
> /nix/store/pl6kzwvjzgw0hm9jzfzy9l4k3d2ki6pp-unit-polkit.service.drv
> /nix/store/a09ycalw92zh26x919dx5hhrplgq3chg-system-units.drv
> /nix/store/i9ij8gl5v2fzx6b814hkcf34v4sid14s-etc.drv
> /nix/store/zvz5qpbxi3wsfvl6vbrvapc9sfkk8ilm-nixos-system-sommerfugl-20.09.1500.edb26126d98.drv
> building '/nix/store/v2cfkd90jqp4j338xn8g243j6vmcqaw1-tester-icons-2020-08-09.drv'...
> unpacking sources
> unpacking source archive /nix/store/9iri7fmnsrdm0b5gh5yfld2vbj0zlbs0-tester
> source root is tester
> patching sources
> configuring
> no configure script, doing nothing
> building
> no Makefile, doing nothing
> glibPreInstallPhase
> installing
> ls: cannot access 'cp': No such file or directory
> /nix/store/jniac5ks5r88acz9ys4q9ywsspbacrk9-tester-icons-2020-08-09/share/icons:
> . ..
> builder for '/nix/store/v2cfkd90jqp4j338xn8g243j6vmcqaw1-tester-icons-2020-08-09.drv' failed with exit code 2
> cannot build derivation '/nix/store/n2xaz27wgkmbdc618ihvjrg1xs68c6jx-system-path.drv': 1 dependencies couldn't be built
> cannot build derivation '/nix/store/zvz5qpbxi3wsfvl6vbrvapc9sfkk8ilm-nixos-system-sommerfugl-20.09.1500.edb26126d98.drv': 1 dependencies couldn't be built
> error: build of '/nix/store/zvz5qpbxi3wsfvl6vbrvapc9sfkk8ilm-nixos-system-sommerfugl-20.09.1500.edb26126d98.drv' failed
The files im trying to copy is located in
/home/anna/Templates/Icons/tester/
it contains the folders 16 / places / and index.theme