TH_NUM=`ps aux | grep Python | grep -v "grep" | wc -l`

• TH_MAX is the maximum number of “threads” that can be executed at the same time.
• The first grep selects the threads that make use of python (you can change this, it depends on your script)
• The second grep excludes the command you issued above
• wc counts the number of lines. The first time the result of the pipe is empty, so wc gives “0″ as result.

#!/bin/bash
TH_MAX=10
for sample in `ls ./data`
do
while [ TRUE ]; do
TH_NUM=`ps aux | grep Python | grep -v "grep" | wc -l`
if [ "$TH_NUM" -le "$TH_MAX" ]
then
echo $( ./analyze_sample.py -s ${sample} ) > /dev/null &
echo -en " ${sample} "
break
else
echo -en "."
sleep 1
fi
done
done

For instance, imagine that your programme has the following arguments:
./myprog -s /source/directory -d /dest/directory -c deep

Then, the script myprog should contain a piece of code like this:


if [ $# -eq 0 ] ; then
echo "Usage: $0 -s -d -c"
exit 1
fi
while [ $# -gt 1 ] ; do
case $1 in
-s) source_dir=$2 ; shift 2 ;;
-d) dest_dir=$2 ; shift 2 ;;
-c) copy_mode=$2 ; shift 2 ;;
*) shift 1 ;;
esac
done


Of course, this is only a hint. Just tailor the decoding according to your needs.

R language

Default parameter values are evaluated when the function definition is executed. This means that the expression is evaluated once, when the function is defined, and that that same “pre-computed” value is used for each call. This is especially important to understand when a default parameter is a mutable object, such as a list or a dictionary: if the function modifies the object (e.g. by appending an item to a list), the default value is in effect modified. This is generally not what was intended. A way around this is to use None as the default, and explicitly test for it in the body of the function, …

Find the whole thing here.

Tutorial on pthreads

And if you wonder why you cannot create more than X threads on your system (for me this was always 382), this forum provides a solution.

Basically, the problem is that each thread created will occupy space for its stack. On my system, the default thread stack size is 8MB. Therefore, after 382, I simply run out of space.

Solution: Change the stack size to a smaller value, unless you really need 8MB.

pthread_attr_t tattr;
size_t size;
size = PTHREAD_STACK_MIN + WHAT_ELSE_YOU_NEED;
pthread_attr_init(&tattr);
pthread_attr_setstacksize(&tattr, size);

Another interesting page on pthreads is this.

can be found online at safari books.

in addition:

just realised that it is not the complete version, just previews. sorry!