使用 shell 脚本解析 csv 行中的名称值对

Question

我的输入看起来像以下 2 行：

TASK1,6,INITIAL,2013-01-15 19:20:40,PREPARING,2013-01-15 19:21:12,SCHEDULED,2013-01-15 19:21:13,TRANSLATING,2013-01-15 19:21:13,LOADING,2013-01-15 19:36:37,COMPLETE,2013-01-15 19:36:42
TASK2,5,INITIAL,2013-01-15 19:20:44,PREPARING,2013-01-15 19:21:13,SCHEDULED,2013-01-15 19:21:14,TRANSLATING,2013-01-15 19:36:37,TERMINAL,2013-01-15 20:28:10

我需要用这些行遍历一个文件，并为每一行计算几个时间差......我在计算等方面很好，但我有一段时间试图弄清楚如何解析这个“可变长度”的名称值对字符串......

基本上，Task# 之后的 # 是“状态”的计数，后跟这些状态及其发生时间。

我想做的是获取其中一条线，并最终得到类似这样的东西，并将值分配给它们各自的变量。 （以第一行为例）：

$TASK_ID=TASK1
$STATUS_COUNT=6
$INITIAL=2013-01-15 19:20:40
$PREPARING=2013-01-15 19:21:12
$SCHEDULED=2013-01-15 19:21:12
$TRANSLATING=2013-01-15 19:21:13
$LOADING=2013-01-15 19:36:37
$COMPLETE=2013-01-15 19:36:42
$TERMINAL=<NULL>

使问题更加复杂的是，如果一个任务被多次提交，它将简单地将下一轮状态附加到第一组，这意味着我最终可能会得到如下输入行：

TASK1,11,INITIAL,2013-01-15 19:20:40,PREPARING,2013-01-15 19:21:12,SCHEDULED,2013-01-15 19:21:13,TRANSLATING,2013-01-15 19:21:13,LOADING,2013-01-15 19:36:37,COMPLETE,2013-01-15 19:36:42,INITIAL,2013-01-15 20:20:40,PREPARING,2013-01-15 20:21:12,SCHEDULED,2013-01-15 20:21:13,TRANSLATING,2013-01-15 20:21:13,TERMINAL,2013-01-15 20:36:42

在这种情况下，我希望我的输出是：

$TASK_ID=TASK1
$STATUS_COUNT=11
$INITIAL=2013-01-15 20:20:40
$PREPARING=2013-01-15 20:21:12
$SCHEDULED=2013-01-15 20:21:12
$TRANSLATING=2013-01-15 20:21:13
$LOADING=<NULL>
$COMPLETE=<NULL>
$TERMINAL=2013-01-15 20:36:42

我很困惑，有人可以帮忙吗？

提前致谢

Answer 1

#!/bin/bash

# Splitting on commas, read the task ID and status count followed by all of the statuses,
# which we'll parse later.
while IFS=, read -r TASK_ID STATUS_COUNT STATUSES; do
(
    # Subtly, but importantly, we put the loop body inside parentheses so each loop
    # iteration runs in a sub-shell. This ensures that the $LOADING, $COMPLETE, etc.
    # variables we set don't leak into future iterations.

    echo "TASK_ID      = $TASK_ID"
    echo "STATUS_COUNT = $STATUS_COUNT"

    # Convert the comma-separated string $STATUSES into an array using `read -a'.
    IFS=, read -ra STATUSES <<< "$STATUSES"

    # Assign the statuses to named variables. A side benefit of this is that only the
    # last value of each status type is used.
    for ((i = 0; i < ${#STATUSES[@]}; i += 2)); do
        declare "${STATUSES[$i]}=${STATUSES[$((i+1))]}"
    done

    # Print each of the statuses, or <NULL> if that stage wasn't listed.
    echo "INITIAL      = ${INITIAL:-<NULL>}"
    echo "PREPARING    = ${PREPARING:-<NULL>}"
    echo "SCHEDULED    = ${SCHEDULED:-<NULL>}"
    echo "TRANSLATING  = ${TRANSLATING:-<NULL>}"
    echo "LOADING      = ${LOADING:-<NULL>}"
    echo "COMPLETE     = ${COMPLETE:-<NULL>}"
    echo "TERMINAL     = ${TERMINAL:-<NULL>}"

    echo
)
done

输出：

$ ./tasks < tasks.txt
TASK_ID      = TASK1
STATUS_COUNT = 6
INITIAL      = 2013-01-15 19:20:40
PREPARING    = 2013-01-15 19:21:12
SCHEDULED    = 2013-01-15 19:21:13
TRANSLATING  = 2013-01-15 19:21:13
LOADING      = 2013-01-15 19:36:37
COMPLETE     = 2013-01-15 19:36:42
TERMINAL     = <NULL>

TASK_ID      = TASK2
STATUS_COUNT = 5
INITIAL      = 2013-01-15 19:20:44
PREPARING    = 2013-01-15 19:21:13
SCHEDULED    = 2013-01-15 19:21:14
TRANSLATING  = 2013-01-15 19:36:37
LOADING      = <NULL>
COMPLETE     = <NULL>
TERMINAL     = 2013-01-15 20:28:10

TASK_ID      = TASK1
STATUS_COUNT = 11
INITIAL      = 2013-01-15 20:20:40
PREPARING    = 2013-01-15 20:21:12
SCHEDULED    = 2013-01-15 20:21:13
TRANSLATING  = 2013-01-15 20:21:13
LOADING      = 2013-01-15 19:36:37
COMPLETE     = 2013-01-15 19:36:42
TERMINAL     = 2013-01-15 20:36:42

---

（格伦杰克曼根据新要求添加编辑）

events=(INITIAL PREPARING SCHEDULED TRANSLATING LOADING COMPLETE TERMINAL)

while IFS=, read -r TASK_ID STATUS_COUNT rest; do
    IFS=, read -ra STATUSES <<< "$rest"

    for (( i=0; i < ${#STATUSES[@]}; i+=2 )); do
        # if this this the initial event, reset all statuses
        if [[ ${STATUSES[i]} == ${events[0]} ]]; then
            for event in "${events[@]}"; do
                declare "$event="
            done
        fi
        declare "${STATUSES[i]}=${STATUSES[i+1]}"
    done
    for var in TASK_ID STATUS_COUNT "${events[@]}"; do
        printf "$%s = %s\n" $var "${!var:-<NULL>}"
    done

done