Please do a code review for the following script:

#!/usr/bin/env sh
set -o errexit
set -o nounset

while true
do
  memavail=$(grep MemAvailable: /proc/meminfo | awk '{print $2}')
  if [ "$memavail" -ge 0 ] && [ "$memavail" -lt 393216 ]
  then
    echo "MemAvailable: $memavail kB, triggering oom-killer"
    printf f > /proc/sysrq-trigger
    sleep 30
  elif [ "$memavail" -ge 393216 ] && [ "$memavail" -lt 524288 ]
    sleep 0.1
  elif [ "$memavail" -ge 524288 ] && [ "$memavail" -lt 1048576 ]
    sleep 1
  else
    sleep 10
  fi
done

Here is a code review for the script:

1. The shebang line #!/usr/bin/env sh specifies the interpreter for the script, in this case the POSIX shell. However, the script uses bash-specific features like printf and the -o option for set. It would be more accurate to use #!/usr/bin/env bash as the shebang line.

2. The set -o errexit and set -o nounset options are useful for error handling. The errexit option causes the script to exit immediately if a command exits with a non-zero exit status. The nounset option causes the script to exit if an unset variable is used. These options can help prevent potential errors and bugs in the script.

3. The while true loop will run indefinitely, so it's important to make sure that the script can exit gracefully when needed. It might be helpful to add a signal handler to allow the script to be terminated cleanly, for example by pressing Ctrl+C.

4. The grep and awk commands are used to extract the MemAvailable value from the /proc/meminfo file. This value is then stored in the memavail variable. It might be more efficient to use the awk command alone to extract the value, rather than using grep and awk separately.

5. The if, elif, and else statements check the value of memavail and take different actions based on the value. It might be more readable to use case statements instead of a series of if and elif statements.

6. The printf command writes the letter f to the /proc/sysrq-trigger file, which triggers the kernel's out-of-memory (OOM) killer to kill a process in order to free up memory. This can be a useful action to take if the system is running low on memory, but it's important to consider the potential consequences of killing a process. It might be more appropriate to send an email or a notification to an administrator, rather than immediately killing a process.

7. The sleep commands pause the script for different amounts of time, depending on the value of memavail. It might be more efficient to use a single sleep command with a variable delay time, rather than multiple sleep commands with fixed delay times.

Overall, the script appears to be trying to monitor the system's available memory and take action if the available memory falls below a certain threshold. However, there are some areas for improvement in terms of error handling, readability, and efficiency.

Мне понравилось Не со всеми пунктами согласен, но в некоторых смысл есть.