20.28 如何向awk脚本中传递外部变量

https://scz.617.cn/unix/201509231030.txt

A: scz 2015-09-23 10:30

有两种办法，一种是单引号，另一种是-v。

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#!/bin/bash

nawk="/bin/nawk"
CURRENT_SHELL_PID=$(echo $$)

#
# 与awk脚本的输出形成对比
#
printf "%u\n" "${CURRENT_SHELL_PID}"

nawkcmd='
    BEGIN   \
    {
        #
        # 为了引用外部变量，必须使用单引号，否则不会发生替换
        #
        current_shell_pid   = "'${CURRENT_SHELL_PID}'"
        printf( "%u\n", current_shell_pid )
    }
'

${nawk} "${nawkcmd}"
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#!/bin/bash

nawk="/bin/nawk"
CURRENT_SHELL_PID=$(echo $$)

#
# 与awk脚本的输出形成对比
#
printf "%u\n" "${CURRENT_SHELL_PID}"

nawkcmd='
    BEGIN   \
    {
        printf( "%u\n", current_shell_pid )
    }
'

#
# 可以指定多个-v
#
${nawk} -v current_shell_pid="${CURRENT_SHELL_PID}" "${nawkcmd}"
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