2012年9月14日 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process which backgrounded myprog...

Minimal POSIX C exit status example. To understand $?, you must first understand the concept of process exit status which is defined by POSIX.

I have a script which uses test command to check if $? (return code of last executed command) is not equal to zero.

2011年9月10日 · When you try to execute a program in unix (one with the executable bit set), the operating system will look at the first few bytes of the file. These form the so-called "magic number", which can be used to decide the format of the program and how to execute it. #! corresponds to the magic number 0x2321 (look it up in an ascii table).

2016年6月28日 · I was trying to combine logical AND & OR in a bash script within if condition. Somehow I am not getting the desired output and it is hard to troubleshoot. I am trying to validate the input para...

2009年11月23日 · POSIX is similar to the UNIX standard, and it is intended to ensure that software written for one POSIX-compliant operating system can run on other POSIX-compliant operating systems without modification. The POSIX standard defines a set of system calls, libraries, and utilities that are commonly found in UNIX-based operating systems.

2016年12月28日 · Which process uses port in unix; 1. netstat -Aan | grep port. root> netstat -Aan | grep 3872. output> f1000e000bb5c3b8 tcp 0 0 *.3872 . LISTEN. 2. rmsock f1000e000bb5c3b8 tcpcb. output> The socket 0xf1000e000bb5c008 is being held by proccess 13959354 (java). 3. ps -ef | grep 13959354

Of course, this applies to bash or generally any popular Unix shell as well; though as @anishsane notes, Bash secretly optimizes bash -c 'command' by actually doing exec command. – tripleee Commented Jul 26, 2016 at 5:21

2012年7月20日 · I tried to close the tomcat using ./shutdown.sh from tomcat /bin directory. But found that the server was not closed properly. And thus I was unable to restartMy tomcat is running on port 8080. I ...

2011年11月22日 · Take a look at Job Control on UNIX systems. If you don't have control of your shell, simply hitting ctrl + C should stop the process. If that doesn't work, you can try ctrl + Z and using the jobs and kill -9 %<job #> to kill it. The '-9' is a …