[CentOS] linux xargs

 

리눅스 쉘 스크립트에서 여러 인수들을 전달해 사용한다.

 

기본 사용법

xargs  [-0prtx]	[-e[eof-str]]  [-i[replace-str]]  [-l[max-lines]]  [-n	max-args] [-s max-chars] [-P max-procs] [--null] [--eof[=eof-str]]
       [--replace[=replace-str]] [--max-lines[=max-lines]] [--interactive] [--max-chars=max-chars]  [--verbose]  [--exit]  [--max-procs=max-procs]
       [--max-args=max-args] [--no-run-if-empty] [--version] [--help] [command [initial-arguments]]

 

 

Manual

NAME
     xargs – construct argument list(s) and execute utility

SYNOPSIS
     xargs [-0oprt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]
           [-J replstr] [-L number] [-n number [-x]] [-P maxprocs] [-s size]
           [utility [argument ...]]

DESCRIPTION
     The xargs utility reads space, tab, newline and end-of-file delimited
     strings from the standard input and executes utility with the strings as
     arguments.

     Any arguments specified on the command line are given to utility upon
     each invocation, followed by some number of the arguments read from the
     standard input of xargs.  This is repeated until standard input is
     exhausted.

     Spaces, tabs and newlines may be embedded in arguments using single
     (`` ' '') or double (``"'') quotes or backslashes (``\'').  Single quotes
     escape all non-single quote characters, excluding newlines, up to the
     matching single quote.  Double quotes escape all non-double quote
     characters, excluding newlines, up to the matching double quote.  Any
     single character, including newlines, may be escaped by a backslash.

---

사용 예제

실행하는 스크립트나 프로그램에 인수들을 전달 할 때 사용하니까

실행 파일을 하나 만들어서 써보자

 

threewords.sh 라는 스크립트 실행 파일이 있다.

#!/bin/bash
if [[ "$#" != 3 ]]; then
    echo "[Error] Three arguments required."
    exit 1
fi

echo "The 1st argument is $1"
echo "The 2nd argument is $2"
echo "The 3rd argument is $3"

 

 

예제1 ) 스크립트에 인자로 바로 넘겨주기

$ echo "Tom likes Jerry" | xargs ./threewords.sh

결과

The 1st argument is Tom
The 2nd argument is Likes
The 3rd argument is Jerry

 

 

 

예제2) 인자를 넘겨 줄때 bash 명령어 활용 (변수를 지정해 넘기기)

# 빈칸 기준으로 split 되어 전달된다.
#        $0  $1    $2
$ echo "Tom Likes Jerry" | xargs bash -c './threeOptions.sh $2 $1 $0'

결과

The 1st argument is Jerry
The 2nd argument is Likes
The 3rd argument is Tom

 

 

참고

redhat xargs man pages

https://www.unix.com/man-page/redhat/1l/xargs/