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1. Top results related to define rematch matrix in linux

   • Define function in unix/linux command line (e.g. BASH)

     Top Answer

     Answered Apr 13, 2017 · 38 votes

     Quoting my answer for a similar question on Ask Ubuntu:

     Functions in bash are essentially named compound commands (or code blocks). From man bash

     :

     Compound Commands A compound command is one of the following: ... { list; } list is simply executed in the current shell environment. list must be terminated with a newline or semicolon. This is known as a group command. ...Shell Function Definitions A shell function is an object that is called like a simple command and executes a compound command with a new set of positional parameters. ... [C]ommand is usually a list of commands between { and }, but may be any command listed under Compound Commands above.

     There's no reason given, it's just the syntax.

     Try with a semicolon after wc -l:

     numresults(){ ls "$1"/RealignerTargetCreator | wc -l; }

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     1/5

   • Linux: what does echo $! in Linux?

     Top Answer

     Answered Jul 06, 2012 · 32 votes

     $! PID of last job running in background.

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     2/5

   • In linux In which file ip address of my system is present

     Top Answer

     Answered Sep 18, 2014 · 1 votes

     It's in the manual man. just run command man ifconfig in your terminal and at bottom it says it comes from these three files:

     FILES /proc/net/socket /proc/net/dev /proc/net/if_inet6

     Hope it works.

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     3/5

   • In Linux C program, how to set a global variable read only in a certain function, while read-write in other functions

     Top Answer

     Answered Jun 04, 2016 · 3 votes

     Your question exhibits one of the several reasons why global variables are generally ill-advised. The generic (i.e. not OS specific) solution is to make the array static and hidden within a translation unit (i.e. not global) with public access functions which can then conditionally provide write access and also bounds-checking.

     For example:

     Array.c

     #include <stdbool.h>static int array[100] ;static bool protected = false ;int read_array( unsigned index ){ return array[index] ;}void protect_array(){ protected = true ;}void unprotect_array(){ protected = false ;}void write_array( unsigned index, int value ){ if( !protected && index < sizeof(array) ) { array[index] = value ; }}size_t sizeof_array(){ return sizeof(array) ;}size_t lengthof_array(){ return sizeof(array) / sizeof(*array) ;}

     That provides global control of read/write access (i.e. at any time the array is either R/W or R/O. It may be that you want to simultaneously provide read/write access to some users and read-only to others. That can be achieved thus:

     Array.c

     static int array[100] ;int* get_array_rw(){ return array ;}const int* get_array_ro(){ return array ;}size_t sizeof_array(){ return sizeof(array) ;}size_t lengthof_array(){ return sizeof(array) / sizeof(*array) ;}

     This method will catch write access attempts via the read-only pointer at compile time. However it still has most of the problems associated with global variables.

     A less generic OS specific method is to use a memory-mapped file for the array and use the access control for the memory-mapped file to impose read-only or read-write semantics:

     size_t array_len = 100 ;int fd = open( "arrayfile", O_RDONLY, 0);if( fd >= 0 ){ int* array = mmap( NULL, array_len * sizeof(int), PROT_READ, MAP_PRIVATE | MAP_POPULATE, fd, 0); // Now array points to read only memory // accessible through normal pointer and array index operations.}

     A further method, but not within the scope of your question is to use C++ and wrap the array in a class and use operator overloading of [] to access the array. This method is identical to the first suggestion, but syntactically allows array-like access like the second and third.

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     4/5

   • Linux to define Custom Shell Command?

     Top Answer

     Answered Dec 17, 2012 · 5 votes

     Try alias

     alias abc="echo The quick brown fox jumps over the lazy dog."-

     you can add it into your ~/.bash_profile to make it valid for all sessions.

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     5/5

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2. medium.com › @linuxadminhacks › understanding-theUnderstanding The $BASH_REMATCH In Bash | by Linux School ...

   medium.com › @linuxadminhacks › understanding-the

   Feb 11, 2024 · $BASH_REMATCH is a special array variable in the Bash shell that stores the results of matching a regular expression using the =~ operator within a script.

3. stackoverflow.com › questions › 37995389regex - bash. regexp using bash_rematch - Stack Overflow

   stackoverflow.com › questions › 37995389

   Jun 23, 2016 · I need a regexp using bash rematch to clean possible single quotes or blank spaces before and after. I know it can be done in this way: var=${var##+([ \'])} var=${var%%+([ \'])} But I need it with BASH_REMATCH (long to explain xd). I'm trying with: [[ ${var} =~ ^([\' ]*)?(.+)([\' ])?$ ]] && var="${BASH_REMATCH[1]}" But it doesn't work.

4. kodekloud.com › blog › regex-shell-scriptBash Regex: How to Use Regex in a Shell Script - DevOps Blog

   kodekloud.com › blog › regex-shell-script

   • Cached

   Oct 24, 2023 · Data validation: Ensuring the data follows a certain format or set of rules. Data transformation: Altering data into a desired format or structure. In this blog post, we'll briefly touch upon what regex is, explore some common regex metacharacters, and demonstrate how to use regex inside Bash scripts.

5. unix.stackexchange.com › questions › 340440Bash test: what does "=~" do? - Unix & Linux Stack Exchange

   unix.stackexchange.com › questions › 340440

   Jan 27, 2017 · The REMATCH bit of the BASH_REMATCH array name comes from "Regular Expression Match", i.e. "RE-Match". In non- bash Bourne-like shells, one may also use expr for limited regular expression matching (using only basic regular expressions).

6. www.bashsupport.com › bash › variablesBash variable $BASH_REMATCH – BashSupport Pro

   www.bashsupport.com › bash › variables

   • Cached

   $BASH_REMATCH is an array and contains the matches of a regular expression. ${BASH_REMATCH[0]} contains the complete match of the regular expression. The remaining elements contain the matches of subexpressions.

7. molk.ch › tips › gnuRegular Expression Matching (REMATCH) - molk.ch

   molk.ch › tips › gnu

   • Cached

   Regular Expression Matching (REMATCH) Match and extract parts of a string using regular expressions.

8. People also ask

   Where does the rematch bit come from?

   • The 'REMATCH' bit in BASH_REMATCH comes from 'Regular Expression Match', i.e. 'RE-Match'. In non-bash Bourne-like shells, one may also use 'expr' for limited regular expression matching (using only basic regular expressions). A small example:

   Bash test: what does "=~" do? - Unix & Linux Stack Exchange

   unix.stackexchange.com/questions/340440/bash-test-what-does-do

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   What does Bash_rematch do?

   • Therefore, BASH_REMATCH will contain the portion of the string that matched this capturing group—specifically, the domain name of the URL. The line domain=${BASH_REMATCH} in the script extracts the domain name from the BASH_REMATCH array, specifically from the first capturing group of the regex match.

   Bash Regex: How to Use Regex in a Shell Script - kodekloud.com

   kodekloud.com/blog/regex-shell-script/

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   What is a faster alternative to bash's regex-matching operator?

   • To complement the existing helpful answers: Using Bash's own regex-matching operator, =~, is a faster alternative in this case, given that you're only matching a single value already stored in a variable:

   bash - How do I use a regex in a shell script? - Stack Overflow

   stackoverflow.com/questions/35919103/how-do-i-use-a-regex-in-a-shell-script

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   How does regex work in Bash?

   • When used within Bash scripts, regex can help automate and streamline a variety of operations. Specifically, regex assists in: Data extraction: Pulling necessary information from text. Data validation: Ensuring the data follows a certain format or set of rules. Data transformation: Altering data into a desired format or structure.

   Bash Regex: How to Use Regex in a Shell Script - kodekloud.com

   kodekloud.com/blog/regex-shell-script/

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9. 7thzero.com › blog › bash-101-part-5-regularBash 101 Part 5: Regular Expressions in Conditional statements

   7thzero.com › blog › bash-101-part-5-regular

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   Bash allows you to compare Literal strings and variables against regular expressions when you use the [ [ (double bracket) and =~ (regex comparator, equal sign tilde) in your if statements. I'll be showing examples and explaining them. Example 1: A simple match. #!/bin/bash.