With oh-my-zsh, ls hides the group field instead of showing colors

Question

I'm using Zsh on macOS Big Sur (11.7.4), and in my Terminal I am trying to look at ownership (user & group) of files in the current folder. I want to know the user as well as the group of my files using the ls -la command.

In the Bash shell on macOS, the command:

ls -la

in the /Users/ folder returns:

drwxr-xr-x   5 root  admin   160 Jan  1  2020 .
drwxr-xr-x  20 root  wheel   640 Jan  1  2020 ..
-rw-r--r--   1 root  wheel     0 Jan  1  2020 .localized
drwxrwxrwt  14 root  wheel   448 Feb 16 00:25 Shared
drwxr-xr-x@ 71 Danran   staff  2272 Feb 17 09:41 Danran

This clearly shows that the user of the /User/Danran folder is "Danran" and the group that it belongs to is "staff".

However, when switching back to Zsh and entering the command ls -la on the /Users/ folder it returns:

total 0
drwxr-xr-x   5 root  160 Jan  1  2020 .
drwxr-xr-x  20 root  640 Jan  1  2020 ..
-rw-r--r--   1 root    0 Jan  1  2020 .localized
drwxrwxrwt  14 root  448 Feb 16 00:25 Shared
drwxr-xr-x+ 71 Danran  2272 Feb 17 09:47 Danran

As you can see, in the Zsh command, it only shows the user name, but does not show the group name.

My question is, how can I get Zsh in macOS to show the username and group name using the ls -la command, and if I can't, what command should I use in Zsh to list both users and groups of files and folders?

UPDATE: The output of the alias command is:

-='cd -'
...=../..
....=../../..
.....=../../../..
......=../../../../..
1='cd -1'
2='cd -2'
3='cd -3'
32x='ykr && rl && ssh 32x'
32xroot='ykr && rl && ssh 32xroot'
4='cd -4'
5='cd -5'
6='cd -6'
7='cd -7'
8='cd -8'
9='cd -9'
CA='2>&1 | cat -A'
G='| grep'
H='| head'
HOMEBREW_NO_AUTO_UPDATE=1
L='| less'
LL='2>&1 | less'
M='| most'
NE='2> /dev/null'
NUL='> /dev/null 2>&1'
P='2>&1| pygmentize -l pytb'
T='| tail'
_='sudo '
ali='nano -c ~/.aliases'
autobrewoff=export
autobrewon=export
bcubc='brew upgrade --cask && brew cleanup'
bcubo='brew update && brew outdated --cask'
bfu='brew upgrade --formula'
bp='nano ~/.bash_profile'
brewp='brew pin'
brewsp='brew list --pinned'
brewup='brew update; brew upgrade; brew update --cask; brew upgrade --cask; brew cleanup; brew doctor'
brewup2='brew upgrade --cask --greedy; brew outdated --cask --greedy --verbose | grep -v '\''(latest)'\'' | awk '\''{print }'\'' | xargs brew cask reinstall'
bubc='brew upgrade && brew cleanup'
bubo='brew update && brew outdated'
bubu='bubo && bubc'
bubug='bubo && bugbc'
bugbc='brew upgrade --greedy && brew cleanup'
buz='brew uninstall --zap'
caskup='brew cu --all'
ccat=colorize_cat
cless=colorize_less
cmds='cat ~/.aliases'
cp='cp -i'
dec2='ykr && rl && ssh dec2'
dec2def='ykr && rl && ssh dec2def'
disks='diskutil list'
dpr10='sudo gdd if=/dev/urandom of=/dev/rdisk10 bs=1M count=50 status=progress'
dpr2='sudo gdd if=/dev/urandom of=/dev/rdisk2 bs=1M count=50 status=progress'
dpr3='sudo gdd if=/dev/urandom of=/dev/rdisk3 bs=1M count=50 status=progress'
dpr4='sudo gdd if=/dev/urandom of=/dev/rdisk4 bs=1M count=50 status=progress'
dpr5='sudo gdd if=/dev/urandom of=/dev/rdisk5 bs=1M count=50 status=progress'
dpr6='sudo gdd if=/dev/urandom of=/dev/rdisk6 bs=1M count=50 status=progress'
dpr7='sudo gdd if=/dev/urandom of=/dev/rdisk7 bs=1M count=50 status=progress'
dpr8='sudo gdd if=/dev/urandom of=/dev/rdisk8 bs=1M count=50 status=progress'
dpr9='sudo gdd if=/dev/urandom of=/dev/rdisk9 bs=1M count=50 status=progress'
dpz10='sudo gdd if=/dev/zero of=/dev/rdisk10 bs=1M count=50 status=progress'
dpz2='sudo gdd if=/dev/zero of=/dev/rdisk2 bs=1M count=50 status=progress'
dpz3='sudo gdd if=/dev/zero of=/dev/rdisk3 bs=1M count=50 status=progress'
dpz4='sudo gdd if=/dev/zero of=/dev/rdisk4 bs=1M count=50 status=progress'
dpz5='sudo gdd if=/dev/zero of=/dev/rdisk5 bs=1M count=50 status=progress'
dpz6='sudo gdd if=/dev/zero of=/dev/rdisk6 bs=1M count=50 status=progress'
dpz7='sudo gdd if=/dev/zero of=/dev/rdisk7 bs=1M count=50 status=progress'
dpz8='sudo gdd if=/dev/zero of=/dev/rdisk8 bs=1M count=50 status=progress'
dpz9='sudo gdd if=/dev/zero of=/dev/rdisk9 bs=1M count=50 status=progress'
dr10='sudo gdd if=/dev/urandom of=/dev/rdisk10 bs=1M status=progress'
dr2='sudo gdd if=/dev/urandom of=/dev/rdisk2 bs=1M status=progress'
dr3='sudo gdd if=/dev/urandom of=/dev/rdisk3 bs=1M status=progress'
dr4='sudo gdd if=/dev/urandom of=/dev/rdisk4 bs=1M status=progress'
dr5='sudo gdd if=/dev/urandom of=/dev/rdisk5 bs=1M status=progress'
dr6='sudo gdd if=/dev/urandom of=/dev/rdisk6 bs=1M status=progress'
dr7='sudo gdd if=/dev/urandom of=/dev/rdisk7 bs=1M status=progress'
dr8='sudo gdd if=/dev/urandom of=/dev/rdisk8 bs=1M status=progress'
dr9='sudo gdd if=/dev/urandom of=/dev/rdisk9 bs=1M status=progress'
dud='du -d 1 -h'
duf='du -sh *'
dz10='sudo gdd if=/dev/zero of=/dev/rdisk10 bs=1M status=progress'
dz2='sudo gdd if=/dev/zero of=/dev/rdisk2 bs=1M status=progress'
dz3='sudo gdd if=/dev/zero of=/dev/rdisk3 bs=1M status=progress'
dz4='sudo gdd if=/dev/zero of=/dev/rdisk4 bs=1M status=progress'
dz5='sudo gdd if=/dev/zero of=/dev/rdisk5 bs=1M status=progress'
dz6='sudo gdd if=/dev/zero of=/dev/rdisk6 bs=1M status=progress'
dz7='sudo gdd if=/dev/zero of=/dev/rdisk7 bs=1M status=progress'
dz8='sudo gdd if=/dev/zero of=/dev/rdisk8 bs=1M status=progress'
dz9='sudo gdd if=/dev/zero of=/dev/rdisk9 bs=1M status=progress'
efi='sudo mkdir /Volumes/ESP && sudo mount -t msdos /dev/disk0s1 /Volumes/ESP/'
egrep='egrep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}'
ej10='diskutil eject /dev/disk9 && echo "Disk 10 Ejected." || "Disk 10 NOT Ejected."'
ej2='diskutil eject /dev/disk2 && echo "Disk 2 Ejected." || "Disk 2 NOT Ejected."'
ej3='diskutil eject /dev/disk3 && echo "Disk 3 Ejected." || "Disk 3 NOT Ejected."'
ej4='diskutil eject /dev/disk4 && echo "Disk 4 Ejected." || "Disk 4 NOT Ejected."'
ej5='diskutil eject /dev/disk5 && echo "Disk 5 Ejected." || "Disk 5 NOT Ejected."'
ej6='diskutil eject /dev/disk6 && echo "Disk 6 Ejected." || "Disk 6 NOT Ejected."'
ej7='diskutil eject /dev/disk7 && echo "Disk 7 Ejected." || "Disk 7 NOT Ejected."'
ej8='diskutil eject /dev/disk8 && echo "Disk 8 Ejected." || "Disk 8 NOT Ejected."'
ej9='diskutil eject /dev/disk9 && echo "Disk 9 Ejected." || "Disk 9 NOT Ejected."'
ejefi='diskutil unmount /dev/disk0s1'
fbox='ykr && rl && ssh fbox'
fd='find . -type d -name'
ff='find . -type f -name'
fgrep='fgrep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}'
flushdns='sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder'
g=git
ga='git add'
gaa='git add --all'
gam='git am'
gama='git am --abort'
gamc='git am --continue'
gams='git am --skip'
gamscp='git am --show-current-patch'
gap='git apply'
gapa='git add --patch'
gapt='git apply --3way'
gau='git add --update'
gav='git add --verbose'
gb='git branch'
gbD='git branch --delete --force'
gba='git branch --all'
gbd='git branch --delete'
gbda='git branch --no-color --merged | command grep -vE "^([+*]|\s*($(git_main_branch)|$(git_develop_branch))\s*$)" | command xargs git branch --delete 2>/dev/null'
gbl='git blame -b -w'
gbnm='git branch --no-merged'
gbr='git branch --remote'
gbs='git bisect'
gbsb='git bisect bad'
gbsg='git bisect good'
gbsr='git bisect reset'
gbss='git bisect start'
gc='git commit --verbose'
'gc!'='git commit --verbose --amend'
gca='git commit --verbose --all'
'gca!'='git commit --verbose --all --amend'
gcam='git commit --all --message'
'gcan!'='git commit --verbose --all --no-edit --amend'
'gcans!'='git commit --verbose --all --signoff --no-edit --amend'
gcas='git commit --all --signoff'
gcasm='git commit --all --signoff --message'
gcb='git checkout -b'
gcd='git checkout $(git_develop_branch)'
gcf='git config --list'
gcl='git clone --recurse-submodules'
gclean='git clean --interactive -d'
gcm='git checkout $(git_main_branch)'
gcmsg='git commit --message'
'gcn!'='git commit --verbose --no-edit --amend'
gco='git checkout'
gcor='git checkout --recurse-submodules'
gcount='git shortlog --summary --numbered'
gcp='git cherry-pick'
gcpa='git cherry-pick --abort'
gcpc='git cherry-pick --continue'
gcs='git commit --gpg-sign'
gcsm='git commit --signoff --message'
gcss='git commit --gpg-sign --signoff'
gcssm='git commit --gpg-sign --signoff --message'
gd='git diff'
gd10='sudo gdisk /dev/disk10'
gd2='sudo gdisk /dev/disk2'
gd3='sudo gdisk /dev/disk3'
gd4='sudo gdisk /dev/disk4'
gd5='sudo gdisk /dev/disk5'
gd6='sudo gdisk /dev/disk6'
gd7='sudo gdisk /dev/disk7'
gd8='sudo gdisk /dev/disk8'
gd9='sudo gdisk /dev/disk9'
gdca='git diff --cached'
gdct='git describe --tags $(git rev-list --tags --max-count=1)'
gdcw='git diff --cached --word-diff'
gds='git diff --staged'
gdt='git diff-tree --no-commit-id --name-only -r'
gdup='git diff @{upstream}'
gdw='git diff --word-diff'
gf='git fetch'
gfa='git fetch --all --prune --jobs=10'
gfg='git ls-files | grep'
gfo='git fetch origin'
gg='git gui citool'
gga='git gui citool --amend'
ggpull='git pull origin "$(git_current_branch)"'
ggpur=ggu
ggpush='git push origin "$(git_current_branch)"'
ggsup='git branch --set-upstream-to=origin/$(git_current_branch)'
ghh='git help'
gignore='git update-index --assume-unchanged'
gignored='git ls-files -v | grep "^[[:lower:]]"'
git-svn-dcommit-push='git svn dcommit && git push github $(git_main_branch):svntrunk'
github='ykr && rl && ssh github'
gk='\gitk --all --branches &!'
gke='\gitk --all $(git log --walk-reflogs --pretty=%h) &!'
gl='git pull'
glg='git log --stat'
glgg='git log --graph'
glgga='git log --graph --decorate --all'
glgm='git log --graph --max-count=10'
glgp='git log --stat --patch'
glo='git log --oneline --decorate'
globurl='noglob urlglobber '
glod='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ad) %C(bold blue)<%an>%Creset'\'
glods='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ad) %C(bold blue)<%an>%Creset'\'' --date=short'
glog='git log --oneline --decorate --graph'
gloga='git log --oneline --decorate --graph --all'
glol='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ar) %C(bold blue)<%an>%Creset'\'
glola='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ar) %C(bold blue)<%an>%Creset'\'' --all'
glols='git log --graph --pretty='\''%Cred%h%Creset -%C(auto)%d%Creset %s %Cgreen(%ar) %C(bold blue)<%an>%Creset'\'' --stat'
glp=_git_log_prettily
gluc='git pull upstream $(git_current_branch)'
glum='git pull upstream $(git_main_branch)'
gm='git merge'
gma='git merge --abort'
gmom='git merge origin/$(git_main_branch)'
gmtl='git mergetool --no-prompt'
gmtlvim='git mergetool --no-prompt --tool=vimdiff'
gmum='git merge upstream/$(git_main_branch)'
gp='git push'
gpd='git push --dry-run'
gpf='git push --force-with-lease --force-if-includes'
'gpf!'='git push --force'
gpoat='git push origin --all && git push origin --tags'
gpod='git push origin --delete'
gpr='git pull --rebase'
gpristine='git reset --hard && git clean --force -dfx'
gpsup='git push --set-upstream origin $(git_current_branch)'
gpsupf='git push --set-upstream origin $(git_current_branch) --force-with-lease --force-if-includes'
gpu='git push upstream'
gpv='git push --verbose'
gr='git remote'
gra='git remote add'
grb='git rebase'
grba='git rebase --abort'
grbc='git rebase --continue'
grbd='git rebase $(git_develop_branch)'
grbi='git rebase --interactive'
grbm='git rebase $(git_main_branch)'
grbo='git rebase --onto'
grbom='git rebase origin/$(git_main_branch)'
grbs='git rebase --skip'
grep='grep --color'
grev='git revert'
grh='git reset'
grhh='git reset --hard'
grm='git rm'
grmc='git rm --cached'
grmv='git remote rename'
groh='git reset origin/$(git_current_branch) --hard'
grrm='git remote remove'
grs='git restore'
grset='git remote set-url'
grss='git restore --source'
grst='git restore --staged'
grt='cd "$(git rev-parse --show-toplevel || echo .)"'
gru='git reset --'
grup='git remote update'
grv='git remote --verbose'
gsb='git status --short --branch'
gsd='git svn dcommit'
gsh='git show'
gsi='git submodule init'
gsps='git show --pretty=short --show-signature'
gsr='git svn rebase'
gss='git status --short'
gst='git status'
gsta='git stash push'
gstaa='git stash apply'
gstall='git stash --all'
gstc='git stash clear'
gstd='git stash drop'
gstl='git stash list'
gstp='git stash pop'
gsts='git stash show --text'
gstu='gsta --include-untracked'
gsu='git submodule update'
gsw='git switch'
gswc='git switch --create'
gswd='git switch $(git_develop_branch)'
gswm='git switch $(git_main_branch)'
gtl='gtl(){ git tag --sort=-v:refname -n --list "${1}*" }; noglob gtl'
gts='git tag --sign'
gtv='git tag | sort -V'
gunignore='git update-index --no-assume-unchanged'
gunwip='git log --max-count=1 | grep -q -c "\--wip--" && git reset HEAD~1'
gup='git pull --rebase'
gupa='git pull --rebase --autostash'
gupav='git pull --rebase --autostash --verbose'
gupom='git pull --rebase origin $(git_main_branch)'
gupomi='git pull --rebase=interactive origin $(git_main_branch)'
gupv='git pull --rebase --verbose'
gwch='git whatchanged -p --abbrev-commit --pretty=medium'
gwip='git add -A; git rm $(git ls-files --deleted) 2> /dev/null; git commit --no-verify --no-gpg-sign --message "--wip-- [skip ci]"'
gwt='git worktree'
gwta='git worktree add'
gwtls='git worktree list'
gwtmv='git worktree move'
gwtrm='git worktree remove'
h=history
help=man
hgrep='fc -El 0 | grep'
hidefiles='defaults write com.apple.finder AppleShowAllFiles -bool false && killall Finder'
history='omz_history -f'
hosts='sudo nano /etc/hosts'
ipinfo=$'echo "Your current public ip address is... \t" && curl https://ipinfo.io/ip'
kh='nano ~/.ssh/known_hosts'
l='ls -lFh'
l.='ls -d .* --color=auto'
lS='ls -1FSsh'
la='ls -lAFh'
lanscan='arp-scan -l'
lanscan2='arp -a'
lart='ls -1Fcart'
ldot='ls -ld .*'
listcasks='brew search --casks --desc '\'\'
ll='ls -la'
lr='ls -tRFh'
lrt='ls -1Fcrt'
ls='ls -G'
lsa='ls -lah'
lsn='ls -1'
lsr='ls -lARFh'
lt='ls -ltFh'
maildel='echo '\''d *'\'' | mail -N'
mailsaved='mail -f ~/mbox'
md='mkdir -p'
mv='mv -i'
nano='nano -c'
nmap_check_for_firewall='sudo nmap -sA -p1-65535 -v -T4'
nmap_check_for_vulns='nmap --script=vuln'
nmap_detect_versions='sudo nmap -sV -p1-65535 -O --osscan-guess -T4 -Pn'
nmap_fast='nmap -F -T5 --version-light --top-ports 300'
nmap_fin='sudo nmap -sF -v'
nmap_full='sudo nmap -sS -T4 -PE -PP -PS80,443 -PY -g 53 -A -p1-65535 -v'
nmap_full_udp='sudo nmap -sS -sU -T4 -A -v -PE -PS22,25,80 -PA21,23,80,443,3389 '
nmap_full_with_scripts='sudo nmap -sS -sU -T4 -A -v -PE -PP -PS21,22,23,25,80,113,31339 -PA80,113,443,10042 -PO --script all '
nmap_list_interfaces='nmap --iflist'
nmap_open_ports='nmap --open'
nmap_ping_scan='nmap -n -sP'
nmap_ping_through_firewall='nmap -PS -PA'
nmap_slow='sudo nmap -sS -v -T1'
nmap_traceroute='sudo nmap -sP -PE -PS22,25,80 -PA21,23,80,3389 -PU -PO --traceroute '
nmap_web_safe_osscan='sudo nmap -p 80,443 -O -v --osscan-guess --fuzzy '
odmt='telnet 149.28.125.6 25'
odmtd='telnet mail.facl.xyz 25'
ofd='open_command $PWD'
p='ps -f'
path='echo "Your current path is" && echo $PATH'
privdns=$'echo "Your current private DNS Server is ...\t" && grep "nameserver" /etc/resolv.conf'
privip=$'echo "Your current private IP Address is ...\t" && ipconfig getifaddr en0'
psmo='curl -I -p https://www.mcmo.is'
pubip=$'echo "Your current public IP Address is...\t\t" && curl https://ipinfo.io/ip'
rd=rmdir
rl='source ~/.zshrc && echo "File .zshrc reloaded correctly" || echo "Syntax error, could not import the .zshrc"'
rm='rm -i'
run-help=man
sali='source ~/.aliases && echo "File ~/.aliases reloaded (sourced) correctly" || echo "File ~/.aliases didn not reload (was NOT sourced) correctly. please check your syntax and try again."'
sconf=' nano -c ~/.ssh/config'
sgrep='grep -R -n -H -C 5 --exclude-dir={.git,.svn,CVS} '
showfiles='defaults write com.apple.finder AppleShowAllFiles -bool true && killall Finder'
sortnr='sort -n -r'
ssl=ssllabs-scan
st=speedtest
stubbyconf='nano /usr/local/etc/stubby/stubby.yml'
surf='ssh surf'
t='tail -f'
um10='diskutil unmountDisk /dev/disk10 && echo "Disk 10 unmounted." || "Disk 10 NOT unmounted."'
um2='diskutil unmountDisk /dev/disk2 && echo "Disk 2 unmounted." || "Disk 2 NOT unmounted."'
um3='diskutil unmountDisk /dev/disk3 && echo "Disk 3 unmounted." || "Disk 3 NOT unmounted."'
um4='diskutil unmountDisk /dev/disk4 && echo "Disk 4 unmounted." || "Disk 4 NOT unmounted."'
um5='diskutil unmountDisk /dev/disk5 && echo "Disk 5 unmounted." || "Disk 5 NOT unmounted."'
um6='diskutil unmountDisk /dev/disk6 && echo "Disk 6 unmounted." || "Disk 6 NOT unmounted."'
um7='diskutil unmountDisk /dev/disk7 && echo "Disk 7 unmounted." || "Disk 7 NOT unmounted."'
um8='diskutil unmountDisk /dev/disk8 && echo "Disk 8 unmounted." || "Disk 8 NOT unmounted."'
um9='diskutil unmountDisk /dev/disk9 && echo "Disk 9 unmounted." || "Disk 9 NOT unmounted."'
umefi='diskutil unmount /dev/disk0s1'
unexport=unset
uuid='python -c '\''import sys,uuid; sys.stdout.write(uuid.uuid4().hex)'\'' | pbcopy && pbpaste && echo'
which-command=whence
ykr='gpg-connect-agent "scd serialno" "learn --force" /bye'
yks='gpg --card-status'
zrc='nano ~/.zshrc'
zshrc='${=EDITOR} ${ZDOTDIR:-$HOME}/.zshrc'

NEW DISCOVERY: I am using oh-my-zsh and have plugins enabled. By disabling oh-my-zsh plugins one by one, I have discovered that the command ls -la works properly in zsh when disabling the gnu-utils plugin for oh-my-zsh. Therein, the answer lies inside of the gnu-utils plugin, but I'm not sure which alias from oh-my-zsh is causing this.

Answer 1

The ls command displays the group field by default. It doesn't matter what shell you invoke it from. If ls doesn't display the group field, it's because your shell configuration has an alias (or, in theory, a function, but in practice it's an alias) that adds an option to disable the group field.

On macOS, there are two plausible implementations of the ls command: the one provided by the system, and the one from GNU coreutils which many people install via one of Homebrew, Macports, etc. With the system ls, the option to turn off the group field is -o. With GNU ls, it's -o or -G or --no-group.

With macOS/FreeBSD ls, the option -G enables colored output. So the most likely explanation for not seeing the group field in ls output, and not seeing colors either, is that you have an alias ls='ls -G' with the intent to enable colored output, but ls is actually the GNU version.

The fix is to check the version of ls (and not just the operating system) when setting up the alias. For example:

if ls --colors -d / >/dev/null 2>/dev/null; then
  # ls is GNU ls
  alias ls='ls --colors'
elif ls --colors -d / >/dev/null 2>/dev/null; then
  # GNU ls is often installed under the name gls
  alias ls='gls --colors'
elif ls -G -d / >/dev/null 2>/dev/null; then
  # ls has a -G option, assume it means to display colors like on FreeBSD
  alias ls='ls -G'
fi

---

Oh-my-zsh has logic like what I showed above, but covering more cases, in lib/theme-and-appearance.zsh. But the logic isn't quite right for Darwin or FreeBSD: it assumes that ls is the system ls. If you've installed GNU coreutils in such a way that ls invokes the GNU version and not the system version, oh-my-zsh sets up the alias incorrectly.

This is a bug in oh-my-zsh, which can be triggered in two cases on macOS or FreeBSD:

• GNU coreutils (specifically ls) are installed under their default name (not with a g prefix) and come before /usr/bin in $PATH.
• GNU ls is available as gls, but you have not set up a color theme for it (by setting the environment variable LS_COLORS or by having a ~/.dircolors file), and you're using the gnu-utils plugin.

Here are some possible workarounds:

• Set up zsh on your own instead of using oh-my-zsh, which is complex and opinionated.
• Use an oh-my-zsh theme that defines LS_COLORS, or define it yourself with dircolors. You can write a file `~/.dircolors`` and oh-my-zsh will read it for you.
• At the end of ~/.zshrc, manually override the ls alias: if you're running into this problem, alias ls='ls --color' should work for you (as long as you don't share your .zshrc with systems where ls isn't GNU ls).