linux - 函数内的函数未返回预期值

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我的最终目标是处理配置文件并在文件中的特定位置(即特定行)添加条目。

正如您将在下面列出的 shell 脚本中看到的那样(在 Linux (SLES 11) 中运行)，我使用了两个函数:

1. getLine它返回我想要添加条目的行
2. UserEntry它基本上将条目写入指定的行中。

(欢迎任何有关其他方法的建议)。

我面临的问题是，当我调用getLine时从内部UserEntry (方法一)，getLine不返回任何值。基本上就是 grep -q -v 之前的那一行是空的!

我必须从主脚本中单独调用它们(方法2)，即首先调用getLine然后调用UserEntry将 getLine 中的变量值作为参数传递.

这种方法可行，但令我困惑的是为什么第一种方法不行。

这些是配置文件和 bash 脚本:

配置文件snmpd.cnf

#
## SOME STUFF HERE
#
blablabla

# Entry type: usmUserEntry
# Format: usmUserEngineID  (octetString)
#         Normally localSnmpID.
#
#         SOME MORE STUFF HERE
#
# usmUserEntry localSnmpID snmpv3user usmHMACMD5AuthProtocol usmDESPrivProtocol nonVolatile coROopsTransTag "md5pass" "despass"
usmUserEntry localSnmpID snmpv3ops usmHMACSHAAuthProtocol usmAesCfb128Protocol nonVolatile coROopsTransTag "opsauth" "opspriv"
usmUserEntry localSnmpID snmpv3dev usmHMACSHAAuthProtocol usmAesCfb128Protocol nonVolatile coROopsTransTag "devauth" "devpriv"    
#
## SOME STUFF HERE
#
blablabla

Shell 脚本 addline.sh

#!/bin/sh

CIAGT_CNF=./snmpd.cnf
Username=FooDoe
AuthPasswd=A^thP@swd
EncrKey=3ncrKev

getLine() {
    section=0
    currentline=0
    prevline=0
    while read line; do
        echo "$line" | grep -q "$1"
        if [ $? -eq 0  ]; then
            section=1
            continue
        fi
        echo "$line" | grep -q -v "^#"
        ret=$?
        if [ $ret -eq 0  -a $section -eq 1 ]; then
            currentline=`grep -n "^$line" $CIAGT_CNF | cut -f1 -d":"`
            break
        fi
        echo
    done < $CIAGT_CNF
    prevline=`expr $currentline - 1 `
}

UserEntry() {
    sed "/^usmUserEntry localSnmpID /d" $CIAGT_CNF > /tmp/sed$$
    cat /tmp/sed$$ > $CIAGT_CNF && rm /tmp/sed$$

    ## Calling getLine() from within UserEntry() DID NOT work (was returning all lines)
    ## getLine "^# Entry type: usmUserEntry"

    ## sed "${prevline}a\        ## Uncomment this if you call getLine() above
    sed "${1}a\
    usmUserEntry localSnmpID $Username usmHMACSHAAuthProtocol usmAesCfb128Protocol nonVolatile coROopsTransTag \"$AuthPasswd\" \"$EncrKey\"\\
    usmUserEntry localSnmpID public usmNoAuthProtocol usmNoPrivProtocol nonVolatile coROopsTransTag - -" $CIAGT_CNF > /tmp/sed$$
    cat /tmp/sed$$ > $CIAGT_CNF
}

## MAIN

## Method 1
## NOTE: Uncomment "getline ..." in UserEntry()
## Calling getLine() from within UserEntry() DID NOT work (was returning all lines)...
## UserEntry

## Method 2 (workaround)
## ... so we have to call getLine() first and then UserEntry() passing the value of
## $prevline as a parameter
getLine "^# Entry type: usmUserEntry"
UserEntry $prevline

Answer 1

这是我的 bash 代码。它会在以 usmUserEntry localSnmpID 开头的第一行之前插入一对行。配置文件 $CIAGT_CNF 中的所有其他行都将复制到 /tmp/sed$$ 文件

typeset -i inserted=0
while read line
do
     read f1 f2 _ <<<"${line}"

     if   [ "${f1}${f2}" = usmUserEntrylocalSnmpID ]
     then
          if   [ "$inserted" -eq 0 ]
          then
               echo "
usmUserEntry localSnmpID $Username usmHMACSHAAuthProtocol usmAesCfb128Protocol nonVolatile coROopsTransTag \042$AuthPasswd\042 \042$EncrKey\042
usmUserEntry localSnmpID public usmNoAuthProtocol usmNoPrivProtocol nonVolatile coROopsTransTag - -
"
               inserted=1
          fi
     fi
     # Prints the original text line 
     echo "$line"
done < "$CIAGT_CNF" > /tmp/sed$$

更新:2014-11-06

typeset -i inserted=0
while read line
do
     read f1 f2 f3 f4 _ <<<"${line}"

     if   [ "${f1} ${f2} ${f3} ${f4}" = "# Entry type: usmUserEntry" ]
     then
          echo "$line"

          # Read and print every line starting with '#'
          while read line
          do
               read f1 _ <<<"${line}"
               if   [ "${f1#'#'}" = "${f1}" ]
               then
                    # Exit the inner loop When the first
                    # non-starting '#' line is found.

                    break
               fi
               echo "$line"
          done

          if   [ "$inserted" -eq 0 ]
          then
               echo "
usmUserEntry localSnmpID $Username usmHMACSHAAuthProtocol usmAesCfb128Protocol nonVolatile coROopsTransTag \042$AuthPasswd\042 \042$EncrKey\042
usmUserEntry localSnmpID public usmNoAuthProtocol usmNoPrivProtocol nonVolatile coROopsTransTag - -
"
               inserted=1
          fi
     fi

     # Prints the original text line 
     echo "$line"
done < "$CIAGT_CNF" > /tmp/sed$$

致以诚挚的问候