How does SIGINT relate to the other termination signals such as SIGTERM, SIGQUIT and SIGKILL?

by

SIGTERM and SIGKILL are intended for general purpose “terminate this process” requests. SIGTERM (by default) and SIGKILL (always) will cause process termination. SIGTERM may be caught by the process (e.g. so that it can do its own cleanup if it wants to), or even ignored completely; but SIGKILL cannot be caught or ignored.

SIGINT and SIGQUIT are intended specifically for requests from the terminal: particular input characters can be assigned to generate these signals (depending on the terminal control settings). The default action for SIGINT is the same sort of process termination as the default action for SIGTERM and the unchangeable action for SIGKILL; the default action for SIGQUIT is also process termination, but additional implementation-defined actions may occur, such as the generation of a core dump. Either can be caught or ignored by the process if required.

SIGHUP, as you say, is intended to indicate that the terminal connection has been lost, rather than to be a termination signal as such. But, again, the default action for SIGHUP (if the process does not catch or ignore it) is to terminate the process in the same way as SIGTERM etc. .

There is a table in the POSIX definitions for signal.h which lists the various signals and their default actions and purposes, and the General Terminal Interface chapter includes a lot more detail on the terminal-related signals.

More Related Contents:

  1. What is the meaning of “POSIX”?
  2. Difference between Real User ID, Effective User ID and Saved User ID
  3. grep lines that contain 1 character followed by another character
  4. When should I wrap quotes around a shell variable?
  5. How to convert DOS/Windows newline (CRLF) to Unix newline (LF) in a Bash script
  6. How to cat a file containing code?
  7. What’s the magic of “-” (a dash) in command-line parameters?
  8. What is double dot(..) and single dot(.) in Linux?
  9. What does the number in parentheses shown after Unix command names in manpages mean?
  10. Forcing bash to expand variables in a string loaded from a file
  11. How to instruct cron to execute a job every second week?
  12. How do I use the lines of a file as arguments of a command?
  13. How can I programmatically create a new cron job?
  14. How to concatenate multiple lines of output to one line?
  15. How to split CSV files as per number of rows specified?
  16. How to run a shell script on a Unix console or Mac terminal?
  17. How can I convert a file pointer ( FILE* fp ) to a file descriptor (int fd)?
  18. GROUP BY/SUM from shell
  19. List files recursively in Linux CLI with path relative to the current directory
  20. What is the difference between “source script.sh” and “./script.sh”?
  21. How to print third column to last column?
  22. Monitor Directory for Changes
  23. What is the status of POSIX asynchronous I/O (AIO)?
  24. Is there an equivalent to WinAPI’s MAX_PATH under linux/unix?
  25. don’t fail jenkins build if execute shell fails
  26. How do I get the path of a process in Unix / Linux?
  27. What is path //, how is it different from /
  28. How can I use xargs to copy files that have spaces and quotes in their names?
  29. What is PATH on a Mac (UNIX) system?
  30. Find all files with name containing string [closed]

Leave a Comment