feat(unitproc/bknpass):Make portable if script used in bash function

- feat(unitproc/bknpass):
  - Exit on too many arguments.
  - Remove repeat chars (for future version when charset specified by option)

diff --git a/unitproc/bknpass b/unitproc/bknpass
index 094b7d664aaad93c0b55f79b15b65e91565c2d00..f4930a069b8782cebda61145059034e01c7fc0c3 100755 (executable)
--- a/unitproc/bknpass
+++ b/unitproc/bknpass
@@ -3,7 +3,7 @@
 # Usage: bknpass [integer]
 # Example: bknpass 256
 #   Result: 9tnzcl0m4dsm22a95525zj93jj
-# Version: 0.2.0
+# Version: 0.2.1
 # Depends: bash 5.1.8, GNU coreutils 8.32, bc 1.07.1, awk 5.1.0
 # License:
 #    `bknpass`, an alphanumeric password generator
@@ -52,10 +52,14 @@ main() {
     #             [4] "Logarithms in GNU bc". https://web.archive.org/web/20210211050732/http://phodd.net/gnu-bc/bcfaq.html#bclog
     #             [5] "BIP 173". Note: bech32 charset. https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
     #             [6] "Bash Function to generate random password". https://www.thegeekstuff.com/2010/04/unix-bash-function-examples/
-    charset="qpzry9x8gf2tvdw0s3jn54khce6mua7l"; # bech32. See [2].
+    charset="qpzry9x8gf2tvdw0s3jn54khce6mua7l"; # bech32. See [5].
+    charset="$(tr -s "$charset" < <(echo -n "$charset"))"; # remove repeat chars
     alphabet_size="$(echo -n "$charset" | wc -c)"; # number of unique chars
     log_base=2; # entropy unit base (i.e. 2 for "bits of entropy")
 
+    # Check inputs
+    if [[ $# -gt 1 ]]; then showUsage; die "ERROR:Too many arguments:$#"; fi;
+
     # Check for bc
     if ! command -v bc 1>/dev/null 2>&1; then die "ERROR:bc not available"; fi;
 
@@ -78,7 +82,7 @@ main() {
     ###      a=$alphabet_size
     ###      n=$char_count_float
     ###      b=$entropy_bit_count
-    char_count_float="$(echo "$entropy_bit_count*l($log_base)/l($alphabet_size)" | bc -l)";
+    char_count_float="$(echo "$entropy_bit_count*l($log_base)/l($alphabet_size)" | bc -l)"; # See [4]
 
     ## Round $char_count_float to next highest integer
     char_count="$(echo "$char_count_float" | awk '{print ($0-int($0)>0)?int($0)+1:int($0)}')"; # See [3]
@@ -87,7 +91,7 @@ main() {
     echo "$(LC_ALL=C tr -cd "$charset" < /dev/urandom | head -c "$char_count")"; # See [6]
 }; # main program
 
-main "$@";
+( main "$@" ); # run 'main()' in subshell for 'die()' portability of script as sourced bash function.
 
 #==References==
 #