Merge pull request #32 from pajamian/main

Move some checks to the top of the script.

migrate2rocky/migrate2rocky.sh

@@ -32,6 +32,26 @@
 ## Rocky is RC status. Using this script means you accept all risks of system
 ## instability.
 
+# These checks need to be right at the top because we start with bash-isms right
+# away in this script.
+if [ -n "$POSIXLY_CORRECT" ] || [ -z "$BASH_VERSION" ]; then
+    printf '%s\n' "bash >= 4.0 is required for this script." >&2
+    exit 1
+fi
+
+# We need bash version >= 4 for associative arrays.
+if (( BASH_VERSINFO < 4 )); then
+    printf '%s\n' "bash >= 4.0 is required for this script." >&2
+    exit 1
+fi
+
+# Make sure we're root.
+if (( EUID != 0 )); then
+    printf '%s\n' "You must run this script as root.  Either use sudo or 'su -c ${0}'" >&2
+    exit 1
+fi
+
+
 # Path to logfile
 logfile=/var/log/migrate2rocky.log
 
@@ -114,22 +134,11 @@ pre_check () {
 # work unless it's severly broken.  This is just a simple check that will cause
 # the script to bail if any expected system utilities are missing.
 bin_check() {
-    # Make sure we're root.
-    if (( EUID != 0 )); then
-	exit_message "You must run this script as root.  Either use sudo or 'su -c ${0}'"
-    fi
-
     # Check the platform.
     if [[ $(os-release PLATFORM_ID) != "$SUPPORTED_PLATFORM" ]]; then
 	exit_message "This script must be run on an EL8 distribution.  Migration from other distributions is not supported."
     fi
 
-    # We need bash version >= 4 for associative arrays.  This will also verify
-    # that we're actually running bash.
-    if (( BASH_VERSINFO < 4 )); then
-	exit_message "bash >= 4.0 is required for this script."
-    fi
-
     local -a missing bins
     bins=(
 	rpm dnf awk column tee tput mkdir