$  nix-store --gc --print-roots | grep profiles
removing stale link from '/nix/var/nix/gcroots/auto/jhlmhmdxk32ka0x40rfvx666w36w0fv7' to '/tmp/nix-build-20015-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/my09zy268lcwamwv8sqx0sqf46kzl1bh' to '/tmp/tmp.7822Yg388l/system'
removing stale link from '/nix/var/nix/gcroots/auto/gbyl331dcil4gbnfz8xh2xcmps1pca0p' to '/tmp/tmp.GHMPdGTVfh/system'
removing stale link from '/nix/var/nix/gcroots/auto/b6krqhzak5rji62d66hfpjw3x8hmampa' to '/tmp/nixos-rebuild.wCX9ys/nix'
removing stale link from '/nix/var/nix/gcroots/auto/f8kpxzyqvwhak9c5z0ynml68lppmf01g' to '/tmp/tmp.6y0IrPSvQc/system'
removing stale link from '/nix/var/nix/gcroots/auto/lng4axs2h9h3n7h1vcszlrynsgl8mwn2' to '/tmp/nix-build-16258-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/8g11qbxpcf1njnh2raq970rxbxs1xasz' to '/tmp/nix-build-13765-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/zxqqr51qpb1a784bqzics96cq402psfj' to '/tmp/tmp.b1p7BYjK63/system'
removing stale link from '/nix/var/nix/gcroots/auto/fp2wpjxq4ij9gxhwbbwbjcjb8w5kcd4c' to '/tmp/tmp.dHDBwFFNps/system'
removing stale link from '/nix/var/nix/gcroots/auto/bd2ck53bbzlw295gr38lii1wiff8ymiq' to '/tmp/nixos-rebuild.XvwK5w/nix'
removing stale link from '/nix/var/nix/gcroots/auto/gd44kzy8fbpff93j1bjr2d070w52k4lp' to '/tmp/nixos-rebuild.WnaQDf/nix.drv'
removing stale link from '/nix/var/nix/gcroots/auto/ql4jlzg3k7sh8hihspcv3fwqinjk0dm1' to '/tmp/nixos-rebuild.xE8s3W/nix'
removing stale link from '/nix/var/nix/gcroots/auto/clmlkf1f1l44984xqxcw3vmpw786mr6v' to '/tmp/nixos-rebuild.xE8s3W/nix.drv'
removing stale link from '/nix/var/nix/gcroots/auto/7ghydsfa55yfw966qarglzd4r7yh288n' to '/tmp/nixos-rebuild.WnaQDf/nix'
removing stale link from '/nix/var/nix/gcroots/auto/ybpkqrljcxg9849m94cd65j6glj2hivw' to '/tmp/nix-build-19954-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/4p7nbzfdkhb7g8nmymyqalvxpn1iypb8' to '/tmp/nix-build-22391-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/pyjk6n9mir06vyv5ciyqwzgpmfny9292' to '/tmp/nix-build-20631-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/kx5fs24b31hzrqm95sxzh15i45hcprqx' to '/tmp/nix-build-22328-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/40b6d8mpk18wwb0k5f1qfyf20klqc547' to '/tmp/nixos-rebuild.Swqfpo/nix.drv'
removing stale link from '/nix/var/nix/gcroots/auto/y25p3fz3w0ca2cvr61bxwywc3917bnx5' to '/tmp/nixos-rebuild.Swqfpo/nix'
removing stale link from '/nix/var/nix/gcroots/auto/6g9fjy26glvch1sjh7q6b8ph3j61axpc' to '/tmp/nix-build-16306-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/14npqkf5cmyl6x666scnmyyyjs9n9iy1' to '/tmp/nix-build-17088-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/vvdw1kfr3jlfp8xcnwwpcd927nic89dc' to '/tmp/nix-build-20988-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/6xjj8ifk5xck3j2p5a7mcqpk44an5y2z' to '/tmp/nixos-rebuild.wCX9ys/nix.drv'
removing stale link from '/nix/var/nix/gcroots/auto/n9vpmjk2a9968l47sxrmd5hnw87xr098' to '/tmp/nix-build-3904-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/25z05s63zkb3ri5rls52hdwimlq3lvwv' to '/tmp/tmp.IIIBSmzhWl/system'
removing stale link from '/nix/var/nix/gcroots/auto/a05xvlr516586rc3wvvydp819appr1a4' to '/tmp/nixos-rebuild.XvwK5w/nix.drv'
removing stale link from '/nix/var/nix/gcroots/auto/d22n1wqkya8ja86c4xc0x2xz4k628aw9' to '/tmp/nix-build-3853-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/bd57q2q1dbngw80qb2jyxjpwcblig4pz' to '/tmp/tmp.SUrXs1w3Vw/system'
removing stale link from '/nix/var/nix/gcroots/auto/5nml7bqhn6vyif5l40qd9bk9fwpqd7ql' to '/tmp/tmp.35DvYxSofc/system'
removing stale link from '/nix/var/nix/gcroots/auto/l3d66ijvxl6wkjhw7y027qmxgzgwdgss' to '/tmp/nix-build-13717-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/vhcb00s8ixvsgxwblw7v2yk5i84q5993' to '/tmp/tmp.W220520Suq/system'
removing stale link from '/nix/var/nix/gcroots/auto/5pfvgx5ja4pykscy3iwd7gzzx1gxvv06' to '/tmp/nix-build-20601-0/result'
removing stale link from '/nix/var/nix/gcroots/auto/73ksafkv5ka1z3368bi5v323jwn9vqbl' to '/tmp/nix-build-17036-0/result'
/nix/var/nix/profiles/default-1-link -> /nix/store/a6wsmpv33bdifj1vsxg1a7kk5hwyjipa-user-environment
/nix/var/nix/profiles/per-user/root/channels-1-link -> /nix/store/rbrsprp4093hmyydzmmhklj1skhkrx34-nixos-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-1-link -> /nix/store/pygrr6frfg355g86zjbnizvs2b31459l-nixos-system-mynixos-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-2-link -> /nix/store/bhrd7w0sgxsd5mpckl8h15fngw0na478-nixos-system-mynixos-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-3-link -> /nix/store/sqb78m9h7apkgcb55vp5q1gxfc5vkn38-nixos-system-mynixos-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-4-link -> /nix/store/5574nwk7yvwzi7d2r4ssa5f1km50bw7z-nixos-system-mynixos-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-5-link -> /nix/store/cqla4065alpls9x5cxr2bpc4lqd5337j-nixos-system-pragdesk-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-6-link -> /nix/store/7rn2564ghlb7gycap89vgnj38va3pd1r-nixos-system-pragdesk-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-7-link -> /nix/store/z7spwf5zljzdbcclj0z0i9qzw8avr90q-nixos-system-pragdesk-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-8-link -> /nix/store/mqibwgg200vyl1c07bp5z9igjks1954h-nixos-system-pragdesk-18.03.132847.aec217852f2
/nix/var/nix/profiles/system-9-link -> /nix/store/bccr864rd4amd7sq14avqcvp5w7f4qq4-nixos-system-pragdesk-18.03.132847.aec217852f2