What are the special dollar sign shell variables?
Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process …
The UNIX® Standard | www.opengroup.org
May 22, 2025 · The Single UNIX Specification is the standard in which the core interfaces of a UNIX OS are measured. The UNIX standard includes a rich feature set, and its core volumes …
bash - Shell equality operators (=, ==, -eq) - Stack Overflow
unix bash shell script equal comparison operator is not comparing. 1. Equal and not equal operators not ...
What does the line "#!/bin/sh" mean in a UNIX shell script?
Sep 10, 2011 · When you try to execute a program in unix (one with the executable bit set), the operating system will look at the first few bytes of the file. These form the so-called "magic …
unix - How to check permissions of a specific directory ... - Stack ...
In GNU/Linux, try to use ls, namei, getfacl, stat.. For Dir [flying@lempstacker ~]$ ls -ldh /tmp drwxrwxrwt. 23 root root 4.0K Nov 8 15:41 /tmp [flying@lempstacker ~]$ namei -l /tmp f: /tmp …
How to check if $? is not equal to zero in unix shell scripting?
unix; Share. Improve this question. Follow edited Oct 15, 2015 at 20:29. Keith Thompson. 265k 46 46 gold ...
In Unix, how do you remove everything in the current directory …
May 4, 2009 · First, if you look at the rm command man page (man rm under most Unix) you notice that –r means "remove the contents of directories recursively". So, doing rm -r . alone …
unix - What is the meaning of "POSIX"? - Stack Overflow
Nov 23, 2009 · 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 …
unix - How to get PID of process by specifying process name and …
Jul 3, 2013 · Solution (Exact Process Name Match) pgrep -x <process_name> | xargs kill -9 (incidentally, for this specific use case, might as well do pkill -9 -x <process_name>, but the …
Boolean operators ( &&, -a, ||, -o ) in Bash - Stack Overflow
Dec 8, 2013 · What is the difference between the &&, ||, -a, and -o Unix operators? What are the restrictions on the usage of both types? Is it simply that the && and || operators should be …