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쉘스크립트에서 php의 explode 함수 기능을 사용하려면 어떻게

kurtof27의 이미지
글쓴이: kurtof27 / 작성시간: 화, 2004/05/18 - 3:14오후

현재 도메인이 eee.star.com 이라면

eee와 star 그리고 star.com 이 각각 변수로 필요한데요

$a = eee;
$b = star;
$c = star.com;

이렇게 필요한데 쉘에서는 explode 기능을 어떻게 해야할지 모르겠어요
제발 도와주세요.

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nachnine의 이미지

글쓴이: nachnine / 작성시간: 화, 2004/05/18 - 3:21오후 

#!/bin/bash

a="www.yahoo.com"

b=` echo $a | cut -d. -f1 ` 
echo $b

b=` echo $a | cut -d. -f2 ` 
echo $b

b=` echo $a | cut -d. -f2,3 ` 
echo $b

더 좋은 방법은 다른 분께서 달아주실겁니다.

alfalf의 이미지

글쓴이: alfalf / 작성시간: 화, 2004/05/18 - 5:44오후 

IFS='.'; echo "eee.star.com" | (read a b c; echo $a; echo $b; echo "$b.$c")
eee
star
star.com

단, a, b, c 변수는 괄호안에서만 유효합니다. 이유는

BASH FAQ wrote:
E4) If I pipe the output of a command into `read variable', why doesn't
the output show up in $variable when the read command finishes?

This has to do with the parent-child relationship between Unix
processes. It affects all commands run in pipelines, not just
simple calls to `read'. For example, piping a command's output
into a `while' loop that repeatedly calls `read' will result in
the same behavior.

Each element of a pipeline runs in a separate process, a child of
the shell running the pipeline. A subprocess cannot affect its
parent's environment. When the `read' command sets the variable
to the input, that variable is set only in the subshell, not the
parent shell. When the subshell exits, the value of the variable
is lost.

Many pipelines that end with `read variable' can be converted
into command substitutions, which will capture the output of
a specified command. The output can then be assigned to a
variable:

grep ^gnu /usr/lib/news/active | wc -l | read ngroup

can be converted into

ngroup=$(grep ^gnu /usr/lib/news/active | wc -l)

This does not, unfortunately, work to split the text among
multiple variables, as read does when given multiple variable
arguments. If you need to do this, you can either use the
command substitution above to read the output into a variable
and chop up the variable using the bash pattern removal
expansion operators or use some variant of the following
approach.

Say /usr/local/bin/ipaddr is the following shell script:

#! /bin/sh
host `hostname` | awk '/address/ {print $NF}'

Instead of using

/usr/local/bin/ipaddr | read A B C D

to break the local machine's IP address into separate octets, use

OIFS="$IFS"
IFS=.
set -- $(/usr/local/bin/ipaddr)
IFS="$OIFS"
A="$1" B="$2" C="$3" D="$4"

Beware, however, that this will change the shell's positional
parameters. If you need them, you should save them before doing
this.

This is the general approach -- in most cases you will not need to
set $IFS to a different value.

Some other user-supplied alternatives include:

read A B C D << HERE
$(IFS=.; echo $(/usr/local/bin/ipaddr))
HERE

and, where process substitution is available,

read A B C D < <(IFS=.; echo $(/usr/local/bin/ipaddr))

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