diff --git a/.config/zsh/.zprofile b/.config/zsh/.zprofile
index 7a97821..dc0242e 100644
--- a/.config/zsh/.zprofile
+++ b/.config/zsh/.zprofile
@@ -79,7 +79,7 @@ fi
 
 # Use ISO 8601 date & time.
 if [[ "${LC_TIME}" != "en_DK.utf8" ]] && command -v locale > /dev/null; then
-    [[ "$(locale --all-locales)" =~ "en_DK" ]] && export LC_TIME="en_DK.utf8"
+    [[ "$(locale --all-locales)" == *en_DK* ]] && export LC_TIME="en_DK.utf8"
 fi
 
 export CCACHE_DIR="/var/cache/ccache"
diff --git a/.config/zsh/.zshrc b/.config/zsh/.zshrc
index 68e4ce7..6a20795 100644
--- a/.config/zsh/.zshrc
+++ b/.config/zsh/.zshrc
@@ -132,7 +132,7 @@ case ${TERM} in
     (dumb)                      # Emacs shells and TRAMP.
         unsetopt ZLE
 
-        if [[ ${INSIDE_EMACS} =~ "tramp" ]]; then
+        if [[ ${INSIDE_EMACS} == *tramp* ]]; then
             HISTFILE="/dev/null"
         fi
 
diff --git a/.config/zsh/aliases.zsh b/.config/zsh/aliases.zsh
index 9449d7c..649a791 100644
--- a/.config/zsh/aliases.zsh
+++ b/.config/zsh/aliases.zsh
@@ -24,13 +24,13 @@ alias man="LC_MESSAGES=C man"
 alias make="LC_MESSAGES=C make"
 alias free="LC_MESSAGES=C free"
 
-if [[ "${VISUAL}" =~ "emacs(client|remote)" ]]; then
+if [[ ${VISUAL} == *emacs(client|remote)* ]]; then
     local tmp_editor="${VISUAL/ -c/}"
     local ec_opts=""
     # Workaround for <https://emacs.stackexchange.com/q/63843>.
     [[ -z "${DISPLAY}" ]] && ec_opts=" -c"
     alias e="${tmp_editor}${ec_opts}"
-    if [[ "${tmp_editor}" =~ "emacsremote$" ]]; then
+    if [[ "${tmp_editor}" == *emacsremote ]]; then
         alias se="${tmp_editor} --sudo"
     elif pgrep -f "emacs --daemon" > /dev/null; then
         # Edit files as root in the Emacs instance run by the current user.
diff --git a/.config/zsh/keys.zsh b/.config/zsh/keys.zsh
index 65cf53c..cdaa8d5 100644
--- a/.config/zsh/keys.zsh
+++ b/.config/zsh/keys.zsh
@@ -55,7 +55,7 @@ bindkey '^[[1;5D' backward-word        # C-Left
 bindkey '^[[1;5C' forward-word         # C-Right
 
 
-if [[ "${TERM}" =~ "^rxvt" ]]; then
+if [[ "${TERM}" == rxvt* ]]; then
     bindkey '^[[3^'   delete-word
     bindkey '^[Od'    backward-word
     bindkey '^[Oc'    forward-word