+ option -c

par

 #!/bin/bash
 
 time_limit=3600s
+ncpu=$(nproc)
 
 set -e
 
@@ -10,11 +11,12 @@ help ()
 
 Syntax: $1 [-t timelimit]
 
-    Start local executables concurrently,
-    limited by the number of cores reported by 'nproc' ($(nproc) on this host).
+    Start local executables concurrently, limited by default by the number of cores.
+    Logfiles are created for each executable (<execname>-log.txt).
 
 Options:
-    -t timelimit    (default: ${time_limit})
+    -t time-limit                       (default: ${time_limit})
+    -c concurrent number of executables (default: $(nproc) on this host)
 
 EOF
     exit 1
@@ -23,13 +25,13 @@ EOF
 while [ ! -z "$1" ]; do
     case "$1" in
     -t) time_limit="$2"; shift;;
-    -h) help "$0";; 
+    -c) ncpu="$2"; shift;;
+    -h) help "$0";;
     *)  echo "argument $1 not understood"; help "$0"; exit 1;;
     esac
     shift
 done
 
-ncpu=$(nproc)
 pids=.pid
 
 mkdir -p ${pids}
@@ -39,7 +41,7 @@ for exec in *; do
 
     # must be executable
     [ -x ${exec} ] || continue
-    
+
     # log file must not already exist
     [ -r ${exec}-log.txt ] && { echo "${exec}: logfile already exists"; continue; }