Bash：从文件到一个命令参数的多行

Question

我需要将一个文件中的多行作为一个逗号分隔的参数传递到脚本中。每当我尝试使用将文件处理为单个字符串的输出时，逗号就会成为分隔符。我该怎么做？

测试用例：

[user@host]$ #Here is a word list, my target words are on lines starting with "1,"
[user@host]$ cat word_list_numbered.txt
1,lakin
2,chesterfield
3,sparkplug
4,unscrawling
5,sukkah
1,girding
2,gripeful
3,historied
4,hypoglossal
5,nonmathematician
1,instructorship
2,loller
3,containerized
4,duodecimally
5,oligocythemia
1,nonsegregation
2,expecter
3,enterrologist
4,tromometry
5,salvia
[user@host]$ #Here is a mock operation, it just outputs the number of args, I want all selected words as one argument
[user@host]$ cat operation.sh
echo "This script has $# arguments"
[user@host]$ #Here is a script that outputs the needed words as comma delimited
[user@host]$ grep '^1,' word_list_numbered.txt | tr -d '1,' | tr '\n' ',' | sed 's/,$//'        lakin,girding,instructorship,nonsegregation[user@host]$
[user@host]$ #Here is the operation script receiving that comma delimited list
[user@host]$ ./operation.sh $(grep '^1,' word_list_numbered.txt | tr -d '1,' | tr '\n' ',' | sed 's/,$//')
This script has 4 arguments
[user@host]$ #oops, too many arguments
[user@host]$ ./operation.sh foo,bar
This script has 1 arguments
[user@host]$ ./operation.sh foo bar
This script has 2 arguments
[user@host]$

详情：

• 需要的单词在以 1 开头的行中，
• 所有单词都应作为一个逗号分隔的参数传递给 operation.sh
• 我无法控制 word_list_numbered.txt 的格式，也无法控制 operation.sh 将所有单词作为一个逗号分隔的参数
• 多次运行 operation.sh 并不是最佳选择——我在问这个问题，所以我不必这样做

Answer 1

awk 和 xargs 的组合怎么样？

 awk -F, -v ORS=, '$1==1{print $2}' file | xargs ./operation.sh

或者如果你介意结尾的逗号：

 awk -F, -v ORS=, '$1==1{print $2}' file | sed 's/,$//' | xargs ./operation.sh

测试：

$ cat operation.sh 
echo "This script has $# arguments"
echo "$@"

$ awk -F, -v ORS=, '$1==1{print $2}' file | sed 's/,$//' | xargs ./operation.sh 
This script has 1 arguments
lakin,girding,instructorship,nonsegregation

$ cat file
1,lakin
2,chesterfield
3,sparkplug
4,unscrawling
5,sukkah
1,girding
2,gripeful
3,historied
4,hypoglossal
5,nonmathematician
1,instructorship
2,loller
3,containerized
4,duodecimally
5,oligocythemia
1,nonsegregation
2,expecter
3,enterrologist
4,tromometry
5,salvia

---

如果没有 xargs，它将是：

./operation.sh "$(awk -F, -v ORS=, '$1==1{print $2}' file | sed 's/,$//')"

Answer 2

给定：

$ echo "$tgt"
1,lakin
2,chesterfield
3,sparkplug
4,unscrawling
5,sukkah
1,girding
2,gripeful
3,historied
4,hypoglossal
5,nonmathematician
1,instructorship
2,loller
3,containerized
4,duodecimally
5,oligocythemia
1,nonsegregation
2,expecter
3,enterrologist
4,tromometry
5,salvia

在 Perl 中：

$ echo "$tgt" | perl -F',' -lane '$A[++$#A]=$F[1] if $F[0]=="1"; END{ print join(",", @A) }'
lakin,girding,instructorship,nonsegregation

Answer 3

awk 的替代方法是在 bash 中使用 命令替换 来用文件的内容填充数组，然后再次将所有行连接成一个逗号分隔的字符串以传递给 @ 987654322@:

#!/bin/bash

## function simulating operation.sh
operation() { printf "%s\n" "$1"; }

a=( $(<word_list_numbered.txt) )
b="${a[0]}$(printf ",%s" ${a[@]:1} )"

operation $b

exit 0

输出

$ bash csvlist.sh
1,lakin,2,chesterfield,3,sparkplug,4,unscrawling, ..<snip>.. 5,salvia

Answer 4

通过 awk 过滤并获取单词，然后使用 paste 将它们连接起来。

$ awk -F ',' '$1==1{print $2}' word_list_numbered.txt  | paste -s -d ',' -
lakin,girding,instructorship,nonsegregation
$ ./operation.sh "$(awk -F ',' '$1==1{print $2}' word_list_numbered.txt  | paste -s -d ',' - )"
This script has 1 arguments
$

更新：用双引号括起来。