命令不在bash脚本中

Question

我正在尝试用这个脚本计算一个简单的平均值

 for i in 1 2 3 4;
  do
    acum=0
    for n_proc in 1 2 3 4;
        do
          #obtenemos el comienzo
          start="$(date +'%s%3N')"
          mpirun -np $n_proc ./solver_async
          #obtenemos el final
          end="$(date +'%s%3N')"
          #obtenemos la duracion de la ejecucion
          duration=$(($end-$start))
          acum=$(( $acum + $duration ))

          result="$n_proc  $duration"
          #enviamos los datos al fichero result.dat
        done
        avg=$(( $acum / 4 ))
        echo $avg >> result5.dat
  done

但是它不工作，我有一个语法错误

/opt/gridengine/default/spool/compute-0-8/job_scripts/459539: line 21: syntax error near unexpected token `('
/opt/gridengine/default/spool/compute-0-8/job_scripts/459539: line 21: `          acum=(($acum+$duration));'
/opt/gridengine/default/spool/compute-0-8/job_scripts/459539: line 25: syntax error near unexpected token `done'
/opt/gridengine/default/spool/compute-0-8/job_scripts/459539: line 25: `        done'

Answer 1

您应该将该行替换为

 acum=$acum + $duration;

使用

 acum=$(( $acum + $duration ))

和这条线

avg=$acum/4

使用

avg=$(( $acum / 4 ))