bash 如何在shell脚本中将部分变量提取到另一个变量中
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How to extract part of variable into another variable in shell script
提问by Alexey Kamenskiy
I have a variable which looks like xx-xx-xx-xx where each xx is a number (length of each xx is unknown)
我有一个看起来像 xx-xx-xx-xx 的变量，其中每个 xx 是一个数字（每个 xx 的长度未知）
I need to extract those numbers in separate variables to be able manipulate them. I tried to look at regular expressions but couldnt see any solution (or i am just blind enough not to notice.
我需要在单独的变量中提取这些数字才能操纵它们。我试图查看正则表达式，但看不到任何解决方案（或者我只是盲目地没有注意到。
Ideally solution should look like
理想的解决方案应该看起来像
#!/bin/sh
# assume VARIABLE equals 1234-123-456-890
VARIABLE=
# HERE SOME CODE assigning variables $PART1 $PART2 $PART3 $PART4
echo $PART1-$PART2-$PART3-$PART4
# Output will give us back 1234-123-456-890
I am quite new to shell scripting so i might have missed something.
我对 shell 脚本很陌生，所以我可能错过了一些东西。
回答by FatalError
Using bashyou could use an array like this:
使用bash你可以使用这样的数组：
#!/bin/bash
VARIABLE=1234-123-456-890
PART=(${VARIABLE//-/ })
echo ${PART[0]}-${PART[1]}-${PART[2]}-${PART[3]}
The ${VARIABLE//-/ }expansion changes all - to spaces and then it's split on word boundaries into an array.
该${VARIABLE//-/ }扩张改变了这一切-为空格，然后是单词边界分割成一个数组。
Alternatively, you could use read:
或者，您可以使用read：
#!/bin/bash
VARIABLE=1234-123-456-890
read PART1 PART2 PART3 PART4 <<< "${VARIABLE//-/ }"
echo $PART1-$PART2-$PART3-$PART4
To make it work in sh, you could change it slightly and set IFS, the input field separator:
要使其在 中工作sh，您可以稍微更改它并设置IFS输入字段分隔符：
#!/bin/sh
VARIABLE=1234-123-456-890
old_ifs="$IFS"
IFS=-
read PART1 PART2 PART3 PART4 <<EOF
$VARIABLE
EOF
IFS="$old_ifs"
echo $PART1-$PART2-$PART3-$PART4
Caveat: this was only tested with bashrunning in shmode.
警告：这仅bash在sh模式下运行时进行了测试。
回答by Rony
/bin/shis dash(see section "Parameter Expansion")
/bin/sh是破折号（参见“参数扩展”部分）
#!/bin/sh
# assume VARIABLE equals 1234-123-456-890
VARIABLE=""
PART4="$VARIABLE" # PART4 is 1234-123-456-890
PART1="${PART4%%-*}" # PART1 is 1234
PART4="${PART4#*-}" # PART4 is 123-456-890
PART2="${PART4%%-*}" # PART2 is 123
PART4="${PART4#*-}" # PART4 is 456-890
PART3="${PART4%%-*}" # PART3 is 456
# PART4 is 456-890
PART4="${PART4#*-}" # PART4 is 890
echo "$PART1-$PART2-$PART3-$PART4"
Test for $PART1-$PART2-$PART3-$PART4
测试 $PART1-$PART2-$PART3-$PART4
$ ./test.sh 1234-123-456-890
1234-123-456-890
$ ./test.sh 1234-abc-789-ABCD
1234-abc-789-ABCD
回答by potong
This might work for you:
这可能对你有用：
a="1234-123-456-890"
OIFS=$IFS; IFS=-; b=($a); echo "${b[*]}"; echo "${b[@]}"; IFS=$OIFS; echo "${b[*]}"
1234-123-456-890
1234 123 456 890
1234 123 456 890
echo "${b[0]}"
1234
echo "${b[1]}"
123
echo "${b[2]}"
456
echo "${b[3]}"
890
回答by peon
PART1=`echo $VARIABLE | cut -d'-' -f1`
