feat(unitproc/bkshuf):Exit early if stdout not being read

[BK-2020-03.git] / unitproc / bkshuf

diff --git a/unitproc/bkshuf b/unitproc/bkshuf
index e41d725b9620c82b29b919120da0bbb4a0bef2bb..ff80d8e575b5dee26a3727316fed96a9d9a104f7 100644 (file)
--- a/unitproc/bkshuf
+++ b/unitproc/bkshuf
@@ -1,10 +1,12 @@
 #!/usr/bin/env bash
 # Desc: Mixes input lines while also preserving some neighbors
 # Usage: cat file | bkshuf arg1
-# Version 0.1.1
+# Version 0.2.0
 # Depends: bc 1.07.1, GNU Coreutils 8.32 (shuf)
 # Input: var: arg1  initial lines to output
 
+trap 'exit;' SIGPIPE; # exit early if stdout not being read
+
 # Load env vars
 ## For these numbers of lines of input...
 if [[ ! -v BKSHUF_PARAM_LINEC ]]; then BKSHUF_PARAM_LINEC=1000000; fi;
@@ -88,7 +90,8 @@ consume_line() {
         line="${list_input[$ip]}";
         if [[ -n $line ]]; then
             ##### consume line at index ip
-            printf "%s\n" "$line" & # print to output
+            printf "%s\n" "$line"; # print to output
+
             unset "list_input[$ip]"; # destroy line in list_input array
             ((lc_out++));
             ((lcr--)); # decrement line count remaining lcr
@@ -161,6 +164,7 @@ main() {
     lc_out="0"; # init output line counter
     if [[ -z "$lc_out_max" ]]; then lc_out_max="$lco"; fi;    
     ip="$(shuf -i0-$(( lco - 1 )) -n1)"; # init input index pointer
+    RANDOM="$(shuf -i0-32767 -n1)"; # init Bash PRNG
     n_loop1="0";
     #yell "DEBUG:max_blanks:$max_blanks"
     while [[ $lcr -ge 1 ]] && [[ $lc_out -lt $lc_out_max ]]; do