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 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 …
unix - How can I pretty-print JSON in a shell script? - Stack Overflow
Dec 9, 2008 · From the Unix command-line with Node.js, specifying a filename that contains JSON, and using an indent of ...
unix - Why is 1/1/1970 the "epoch time"? - Stack Overflow
Jun 23, 2011 · The first edition Unix Programmer's Manual dated November 3, 1971 defines the Unix time as "the time since 00:00:00, Jan. 1, 1971, measured in sixtieths of a second". …
unix - How to use echo command to print out content of a text file ...
you could use echo command with cat as command substitution. However, it will replace CR or return (unix: \n) with spaces: $ echo $(cat names.txt) Homer Marge Bart Lisa Maggie Could be …
unix - Diff files present in two different directories - Stack Overflow
Nov 9, 2012 · I have two directories with the same list of files. I need to compare all the files present in both the directories using the diff command. Is there a simple command line option …
linux - How can I recursively find all files in current and subfolders ...
May 5, 2011 · The default way to search for files recursively, and available in most cases is. find . -name "filepattern" It starts recursively traversing for filename or pattern from within the current …