bash - 需要帮助在 bash 脚本中使用 grep/egrep 匹配模式

Question

我正在尝试匹配给定字符串的所有字符，但这些字符应该按照给定 bash 脚本的顺序匹配。

while [[ $# -gt 0 ]]; do
  case $1 in
       -i)
    arg=$2
    egrep "*[$arg]*" words.txt 
    shift ;;
  esac
  shift
done

$ sh match_the_pattern.sh -i aei words.txt

应该返回类似的词

abstentious
adventitious
sacrilegiousness

如果您注意到，首先匹配a，然后匹配e，然后匹配i，它们都是按顺序匹配的。此外，整个单词都经过匹配和过滤。

Answer 1

您可以使用 getopts 和一些 bash 参数替换来构造查询字符串。

#!/bin/bash
while getopts 'i:' choice
do
  case "${choice}" in
    i)
     length=${#OPTARG}
     for((count=0;count<length;count++))
     do
      if [ $count -eq 0 ]
      then 
       pattern="${pattern}.*${OPTARG:count:1}.*"
      else
       pattern="${pattern}${OPTARG:count:1}.*"
      fi
     done
    ;;    
  esac
done
# The remaining parameter should be our filename
shift $(($OPTIND - 1))
filename="$1"
# Some error checking based on the parsed values
# Ideally user input should not be trusted, so a security check should
# also be done,omitting that for brevity.
if [ -z "$pattern" ] || [ -z "$filename" ]
then
 echo "-i is must. Also, filename cannot be empty"
 echo "Run the script like ./scriptname -i 'value' -- filename"
else
 grep -i "${pattern}" "$filename"
fi

_{引用this了解更多关于参数替换和this的信息对于 getopts。}