trycatch.sh

Question

我正在编写一个shell脚本，需要检查是否已安装终端应用程序。我想使用TRY / CATCH命令来执行此操作，除非有更简洁的方法。

Answer 1

Bash中是否有TRY CATCH命令？

没有。

Bash并没有像许多编程语言中那样多的奢侈品。

bash中没有try/catch;但是，使用&&或||可以实现类似的行为。

使用||：

如果command1失败，则command2运行如下

command1 || command2

同样，使用&&，如果command2成功，command1将会运行

try/catch的最接近的近似值如下

{ # try

    command1 &&
    #save your output

} || { # catch
    # save log for exception 
}

bash也包含一些错误处理机制，

set -e

如果简单命令失败，它将立即停止您的脚本。我认为这应该是默认行为。由于这些错误几乎总是意味着意外的事情，因此继续执行以下命令并不是“理智”。

为什么不if...else。这是你最好的朋友。

Answer 2

基于我在这里找到的一些答案，我为自己的项目提供了一个小帮手文件：

trycatch.sh

#!/bin/bash

function try()
{
    [[ $- = *e* ]]; SAVED_OPT_E=$?
    set +e
}

function throw()
{
    exit $1
}

function catch()
{
    export ex_code=$?
    (( $SAVED_OPT_E )) && set +e
    return $ex_code
}

function throwErrors()
{
    set -e
}

function ignoreErrors()
{
    set +e
}

这是一个如何使用的示例：

#!/bin/bash
export AnException=100
export AnotherException=101

# start with a try
try
(   # open a subshell !!!
    echo "do something"
    [ someErrorCondition ] && throw $AnException

    echo "do something more"
    executeCommandThatMightFail || throw $AnotherException

    throwErrors # automaticatly end the try block, if command-result is non-null
    echo "now on to something completely different"
    executeCommandThatMightFail

    echo "it's a wonder we came so far"
    executeCommandThatFailsForSure || true # ignore a single failing command

    ignoreErrors # ignore failures of commands until further notice
    executeCommand1ThatFailsForSure
    local result = $(executeCommand2ThatFailsForSure)
    [ result != "expected error" ] && throw $AnException # ok, if it's not an expected error, we want to bail out!
    executeCommand3ThatFailsForSure

    echo "finished"
)
# directly after closing the subshell you need to connect a group to the catch using ||
catch || {
    # now you can handle
    case $ex_code in
        $AnException)
            echo "AnException was thrown"
        ;;
        $AnotherException)
            echo "AnotherException was thrown"
        ;;
        *)
            echo "An unexpected exception was thrown"
            throw $ex_code # you can rethrow the "exception" causing the script to exit if not caught
        ;;
    esac
}

Answer 3

我已经开发了几乎完美的尝试＆amp;在bash中捕获实现，允许您编写如下代码：

try 
    echo 'Hello'
    false
    echo 'This will not be displayed'

catch 
    echo "Error in $__EXCEPTION_SOURCE__ at line: $__EXCEPTION_LINE__!"

你甚至可以将try-catch块嵌入其中！

try {
    echo 'Hello'

    try {
        echo 'Nested Hello'
        false
        echo 'This will not execute'
    } catch {
        echo "Nested Caught (@ $__EXCEPTION_LINE__)"
    }

    false
    echo 'This will not execute too'

} catch {
    echo "Error in $__EXCEPTION_SOURCE__ at line: $__EXCEPTION_LINE__!"
}

代码是我bash boilerplate/framework的一部分。它进一步扩展了try＆amp; amp;通过回溯和异常（以及其他一些不错的功能）来处理错误处理等事情。

以下代码负责试用＆amp; amp;捉：

set -o pipefail
shopt -s expand_aliases
declare -ig __oo__insideTryCatch=0

# if try-catch is nested, then set +e before so the parent handler doesn't catch us
alias try="[[ \$__oo__insideTryCatch -gt 0 ]] && set +e;
           __oo__insideTryCatch+=1; ( set -e;
           trap \"Exception.Capture \${LINENO}; \" ERR;"
alias catch=" ); Exception.Extract \$? || "

Exception.Capture() {
    local script="${BASH_SOURCE[1]#./}"

    if [[ ! -f /tmp/stored_exception_source ]]; then
        echo "$script" > /tmp/stored_exception_source
    fi
    if [[ ! -f /tmp/stored_exception_line ]]; then
        echo "$1" > /tmp/stored_exception_line
    fi
    return 0
}

Exception.Extract() {
    if [[ $__oo__insideTryCatch -gt 1 ]]
    then
        set -e
    fi

    __oo__insideTryCatch+=-1

    __EXCEPTION_CATCH__=( $(Exception.GetLastException) )

    local retVal=$1
    if [[ $retVal -gt 0 ]]
    then
        # BACKWARDS COMPATIBILE WAY:
        # export __EXCEPTION_SOURCE__="${__EXCEPTION_CATCH__[(${#__EXCEPTION_CATCH__[@]}-1)]}"
        # export __EXCEPTION_LINE__="${__EXCEPTION_CATCH__[(${#__EXCEPTION_CATCH__[@]}-2)]}"
        export __EXCEPTION_SOURCE__="${__EXCEPTION_CATCH__[-1]}"
        export __EXCEPTION_LINE__="${__EXCEPTION_CATCH__[-2]}"
        export __EXCEPTION__="${__EXCEPTION_CATCH__[@]:0:(${#__EXCEPTION_CATCH__[@]} - 2)}"
        return 1 # so that we may continue with a "catch"
    fi
}

Exception.GetLastException() {
    if [[ -f /tmp/stored_exception ]] && [[ -f /tmp/stored_exception_line ]] && [[ -f /tmp/stored_exception_source ]]
    then
        cat /tmp/stored_exception
        cat /tmp/stored_exception_line
        cat /tmp/stored_exception_source
    else
        echo -e " \n${BASH_LINENO[1]}\n${BASH_SOURCE[2]#./}"
    fi

    rm -f /tmp/stored_exception /tmp/stored_exception_line /tmp/stored_exception_source
    return 0
}

在GitHub上随意使用，分叉并做出贡献。

Answer 4

在ph检测到错误状态的情况下，

bash不会中止正在运行的执行（除非您设置了-e标志）。由于这种特殊情况（因此通常称为“异常”），提供try/catch的编程语言可以禁止“拯救”。

在bash中，只有相关命令将以退出代码大于0退出，表示错误状态。您当然可以检查，但由于没有任何自动拯救， try / catch 没有意义。它只是缺乏这种背景。

但是，您可以使用子shell来模拟拯救，这些子shell可以在您决定的点终止：

(
  echo "Do one thing"
  echo "Do another thing"
  if some_condition
  then
    exit 3  # <-- this is our simulated bailing out
  fi
  echo "Do yet another thing"
  echo "And do a last thing"
)   # <-- here we arrive after the simulated bailing out, and $? will be 3 (exit code)
if [ $? = 3 ]
then
  echo "Bail out detected"
fi

而不是带有some_condition的{{1}}，您也可以尝试命令，如果失败（退出代码大于0），请摆脱困境：

if

不幸的是，使用这种技术，你只能使用255个不同的退出代码（1..255），并且不能使用任何体面的异常对象。

如果您需要更多信息与模拟异常一起传递，您可以使用子shell的标准输出，但这有点复杂，可能是另一个问题; - ）

在shell上使用上面提到的( echo "Do one thing" echo "Do another thing" some_command || exit 3 echo "Do yet another thing" echo "And do a last thing" ) ...标志，您甚至可以删除明确的-e语句：

exit

Answer 5

正如大家所说，bash没有适当的语言支持的try / catch语法。您可以使用-e参数启动bash，或者在脚本中使用set -e以中止整个bash进程（如果任何命令具有非零退出代码）。（您也可以set +e暂时允许失败的命令。）

因此，模拟try / catch块的一种方法是启动一个子流程来完成启用-e的工作。然后在主进程中，检查子进程的返回码。

Bash支持heredoc字符串，因此您不必编写两个单独的文件来处理此问题。在下面的示例中，TRY heredoc将在单独的bash实例中运行，并启用-e，因此如果任何命令返回非零退出代码，则子进程将崩溃。然后，回到主进程，我们可以检查返回代码来处理catch块。

#!/bin/bash

set +e
bash -e <<TRY
  echo hello
  cd /does/not/exist
  echo world
TRY
if [ $? -ne 0 ]; then
  echo caught exception
fi

它不是一个适当的语言支持的try / catch块，但它可能会为你划伤类似的痒。

Answer 6

您可以使用trap：

try { block A } catch { block B } finally { block C }

转换为：

(
  set -Ee
  function _catch {
    block B
    exit 0  # optional; use if you don't want to propagate (rethrow) error to outer shell
  }
  function _finally {
    block C
  }
  trap _catch ERR
  trap _finally EXIT
  block A
)

Answer 7

有许多类似的解决方案可能有效。下面是一个简单而有效的方法来完成try / catch，并在注释中进行解释。

#!/bin/bash

function a() {
  # do some stuff here
}
function b() {
  # do more stuff here
}

# this subshell is a scope of try
# try
(
  # this flag will make to exit from current subshell on any error
  # inside it (all functions run inside will also break on any error)
  set -e
  a
  b
  # do more stuff here
)
# and here we catch errors
# catch
errorCode=$?
if [ $errorCode -ne 0 ]; then
  echo "We have an error"
  # We exit the all script with the same error, if you don't want to
  # exit it and continue, just delete this line.
  exit $errorCode
fi

Answer 8

你有陷阱http://www.tldp.org/LDP/Bash-Beginners-Guide/html/sect_12_02.html这是不一样的，但你可以用于此目的的其他技术

Answer 9

你可以这样做：

#!/bin/bash
if <command> ; then # TRY
    <do-whatever-you-want>
else # CATCH
    echo 'Exception'
    <do-whatever-you-want>
fi

Answer 10

我可以在“ bash -ue”模式下推荐它：

set -ue
   
false && RET=$? || RET=$? 
echo "expecting 1, got ${RET}"
true && RET=$? || RET=$? 
echo "expecting 0, got ${RET}"

echo "test try...catch"
false && RET=$? || RET=$? 
if [ ${RET} -ne 0 ]; then
  echo "caught error ${RET}"
fi

echo "beware, using '||' before '&&' fails"
echo "  -> memory aid: [A]nd before [O]r in the alphabet"
false || RET=$? && RET=$? 
echo "expecting 1, got ${RET}"
true || RET=$? && RET=$? 
echo "expecting 0, got ${RET}"

Answer 11

假设有问题的终端应用程序名为“ app”（并且您希望它位于$ PATH中）：

# calculate mean
df['new_col'] = df.groupby('school')['notes'].transform('sum')

# now set B school sum to np.nan
df.loc[df['school'] == 'B', 'new_col'] = np.nan

Answer 12

我使用的一件非常简单的事情：

try() {
    "$@" || (e=$?; echo "$@" > /dev/stderr; exit $e)
}

Answer 13

下面是other answer中使用的简化脚本的完整副本。除了其他错误检查之外，还有一个别名，允许用户更改现有别名的名称。语法在下面给出。如果省略new_alias参数，则别名将被删除。

ChangeAlias old_alias [new_alias]

完整的脚本如下所示。

common.GetAlias() {
    local "oldname=${1:-0}"
    if [[ $oldname =~ ^[0-9]+$ && oldname+1 -lt ${#FUNCNAME[@]} ]]; then
        oldname="${FUNCNAME[oldname + 1]}"
    fi
    name="common_${oldname#common.}"
    echo "${!name:-$oldname}"
}

common.Alias() {
    if [[ $# -ne 2 || -z $1 || -z $2 ]]; then
        echo "$(common.GetAlias): The must be only two parameters of nonzero length" >&2
        return 1;
    fi
    eval "alias $1='$2'"
    local "f=${2##*common.}"
    f="${f%%;*}"
    local "v=common_$f"
    f="common.$f"
    if [[ -n ${!v:-} ]]; then
        echo "$(common.GetAlias): $1: Function \`$f' already paired with name \`${!v}'" >&2
        return 1;
    fi
    shopt -s expand_aliases
    eval "$v=\"$1\""
}

common.ChangeAlias() {
    if [[ $# -lt 1 || $# -gt 2 ]]; then
        echo "usage: $(common.GetAlias) old_name [new_name]" >&2
        return "1"
    elif ! alias "$1" &>"/dev/null"; then
        echo "$(common.GetAlias): $1: Name not found" >&2
        return 1;
    fi
    local "s=$(alias "$1")" 
    s="${s#alias $1=\'}"
    s="${s%\'}"
    local "f=${s##*common.}"
    f="${f%%;*}"
    local "v=common_$f"
    f="common.$f"
    if [[ ${!v:-} != "$1" ]]; then
        echo "$(common.GetAlias): $1: Name not paired with a function \`$f'" >&2
        return 1;
    elif [[ $# -gt 1 ]]; then
        eval "alias $2='$s'"
        eval "$v=\"$2\""
    else
        unset "$v"
    fi
    unalias "$1"
}

common.Alias exception             'common.Exception'
common.Alias throw                 'common.Throw'
common.Alias try                   '{ if common.Try; then'
common.Alias yrt                   'common.EchoExitStatus; fi; common.yrT; }'
common.Alias catch                 '{ while common.Catch'
common.Alias hctac                 'common.hctaC -r; done; common.hctaC; }'
common.Alias finally               '{ if common.Finally; then'
common.Alias yllanif               'fi; common.yllaniF; }'
common.Alias caught                'common.Caught'
common.Alias EchoExitStatus        'common.EchoExitStatus'
common.Alias EnableThrowOnError    'common.EnableThrowOnError'
common.Alias DisableThrowOnError   'common.DisableThrowOnError'
common.Alias GetStatus             'common.GetStatus'
common.Alias SetStatus             'common.SetStatus'
common.Alias GetMessage            'common.GetMessage'
common.Alias MessageCount          'common.MessageCount'
common.Alias CopyMessages          'common.CopyMessages'
common.Alias TryCatchFinally       'common.TryCatchFinally'
common.Alias DefaultErrHandler     'common.DefaultErrHandler'
common.Alias DefaultUnhandled      'common.DefaultUnhandled'
common.Alias CallStack             'common.CallStack'
common.Alias ChangeAlias           'common.ChangeAlias'
common.Alias TryCatchFinallyAlias  'common.Alias'

common.CallStack() {
    local -i "i" "j" "k" "subshell=${2:-0}" "wi" "wl" "wn"
    local "format= %*s  %*s  %-*s  %s\n" "name"
    eval local "lineno=('' ${BASH_LINENO[@]})"
    for (( i=${1:-0},j=wi=wl=wn=0; i<${#FUNCNAME[@]}; ++i,++j )); do  
        name="$(common.GetAlias "$i")"
        let "wi = ${#j} > wi ? wi = ${#j} : wi"
        let "wl = ${#lineno[i]} > wl ? wl = ${#lineno[i]} : wl"
        let "wn = ${#name} > wn ? wn = ${#name} : wn"
    done
    for (( i=${1:-0},j=0; i<${#FUNCNAME[@]}; ++i,++j )); do
        ! let "k = ${#FUNCNAME[@]} - i - 1"
        name="$(common.GetAlias "$i")"
        printf "$format" "$wi" "$j" "$wl" "${lineno[i]}" "$wn" "$name" "${BASH_SOURCE[i]}"
    done
}

common.Echo() {
    [[ $common_options != *d* ]] || echo "$@" >"$common_file"
}

common.DefaultErrHandler() {
    echo "Orginal Status: $common_status"
    echo "Exception Type: ERR"
}

common.Exception() {
    common.TryCatchFinallyVerify || return
    if [[ $# -eq 0 ]]; then
        echo "$(common.GetAlias): At least one parameter is required" >&2
        return "1"         
    elif [[ ${#1} -gt 16 || -n ${1%%[0-9]*} || 10#$1 -lt 1 || 10#$1 -gt 255 ]]; then
        echo "$(common.GetAlias): $1: First parameter was not an integer between 1 and 255" >&2
        return "1"
    fi
    let "common_status = 10#$1"
    shift
    common_messages=()
    for message in "$@"; do
        common_messages+=("$message")
    done
    if [[ $common_options == *c* ]]; then
        echo "Call Stack:" >"$common_fifo"
        common.CallStack "2" >"$common_fifo"
    fi
}

common.Throw() {
    common.TryCatchFinallyVerify || return
    local "message"
    if ! common.TryCatchFinallyExists; then
        echo "$(common.GetAlias): No Try-Catch-Finally exists" >&2
        return "1"        
    elif [[ $# -eq 0 && common_status -eq 0 ]]; then
        echo "$(common.GetAlias): No previous unhandled exception" >&2 
        return "1"
    elif [[ $# -gt 0 && ( ${#1} -gt 16 || -n ${1%%[0-9]*} || 10#$1 -lt 1 || 10#$1 -gt 255 ) ]]; then
        echo "$(common.GetAlias): $1: First parameter was not an integer between 1 and 255" >&2
        return "1"
    fi
    common.Echo -n "In Throw ?=$common_status "
    common.Echo "try=$common_trySubshell subshell=$BASH_SUBSHELL #=$#"
    if [[ $common_options == *k* ]]; then
        common.CallStack "2" >"$common_file"
    fi
    if [[ $# -gt 0 ]]; then
        let "common_status = 10#$1"
        shift
        for message in "$@"; do
            echo "$message" >"$common_fifo"
        done
        if [[ $common_options == *c* ]]; then
            echo "Call Stack:" >"$common_fifo"
            common.CallStack "2" >"$common_fifo"
        fi
    elif [[ ${#common_messages[@]} -gt 0 ]]; then
        for message in "${common_messages[@]}"; do
            echo "$message" >"$common_fifo"
        done
    fi
    chmod "0400" "$common_fifo"
    common.Echo "Still in Throw $=$common_status subshell=$BASH_SUBSHELL #=$# -=$-"
    exit "$common_status"
}

common.ErrHandler() {
    common_status=$?
    trap ERR
    common.Echo -n "In ErrHandler ?=$common_status debug=$common_options "
    common.Echo "try=$common_trySubshell subshell=$BASH_SUBSHELL order=$common_order"
    if [[ -w "$common_fifo" ]]; then
        if [[ $common_options != *e* ]]; then
            common.Echo "ErrHandler is ignoring"
            common_status="0"
            return "$common_status" # value is ignored
        fi
        if [[ $common_options == *k* ]]; then
            common.CallStack "2" >"$common_file"
        fi
        common.Echo "Calling ${common_errHandler:-}"
        eval "${common_errHandler:-} \"${BASH_LINENO[0]}\" \"${BASH_SOURCE[1]}\" \"${FUNCNAME[1]}\" >$common_fifo <$common_fifo"
        if [[ $common_options == *c* ]]; then
            echo "Call Stack:" >"$common_fifo"
            common.CallStack "2" >"$common_fifo"
        fi
        chmod "0400" "$common_fifo"
    fi
    common.Echo "Still in ErrHandler $=$common_status subshell=$BASH_SUBSHELL -=$-"
    if [[ common_trySubshell -eq BASH_SUBSHELL ]]; then
        return "$common_status" # value is ignored   
    else
        exit "$common_status"
    fi
}

common.Token() {
    local "name"
    case $1 in
    b) name="before";;
    t) name="$common_Try";;
    y) name="$common_yrT";;
    c) name="$common_Catch";;
    h) name="$common_hctaC";;
    f) name="$common_yllaniF";;
    l) name="$common_Finally";;
    *) name="unknown";;
    esac
    echo "$name"
}

common.TryCatchFinallyNext() {
    common.ShellInit
    local "previous=$common_order" "errmsg"
    common_order="$2"
    if [[ $previous != $1 ]]; then
        errmsg="${BASH_SOURCE[2]}: line ${BASH_LINENO[1]}: syntax error_near unexpected token \`$(common.Token "$2")'"
        echo "$errmsg" >&2
        [[ /dev/fd/2 -ef $common_file ]] || echo "$errmsg" >"$common_file"
        kill -s INT 0
        return "1"        
    fi
}

common.ShellInit() {
    if [[ common_initSubshell -ne BASH_SUBSHELL ]]; then
        common_initSubshell="$BASH_SUBSHELL"
        common_order="b"
    fi
}

common.Try() {
    common.TryCatchFinallyVerify || return
    common.TryCatchFinallyNext "[byhl]" "t" || return 
    common_status="0"
    common_subshell="$common_trySubshell"
    common_trySubshell="$BASH_SUBSHELL"
    common_messages=()
    common.Echo "-------------> Setting try=$common_trySubshell at subshell=$BASH_SUBSHELL"
}

common.yrT() {
    local "status=$?"
    common.TryCatchFinallyVerify || return
    common.TryCatchFinallyNext "[t]" "y" || return 
    common.Echo -n "Entered yrT ?=$status status=$common_status "
    common.Echo "try=$common_trySubshell subshell=$BASH_SUBSHELL"
    if [[ common_status -ne 0 ]]; then    

        common.Echo "Build message array. ?=$common_status, subshell=$BASH_SUBSHELL"
        local "message=" "eof=TRY_CATCH_FINALLY_END_OF_MESSAGES_$RANDOM"
        chmod "0600" "$common_fifo"
        echo "$eof" >"$common_fifo"
        common_messages=()
        while read "message"; do

            common.Echo "----> $message"

            [[ $message != *$eof ]] || break
            common_messages+=("$message")
        done <"$common_fifo"
    fi

    common.Echo "In ytT status=$common_status"
    common_trySubshell="$common_subshell"
}

common.Catch() {
    common.TryCatchFinallyVerify || return
    common.TryCatchFinallyNext "[yh]" "c" || return 
    [[ common_status -ne 0 ]] || return "1"
    local "parameter" "pattern" "value"
    local "toggle=true" "compare=p" "options=$-"
    local -i "i=-1" "status=0"
    set -f
    for parameter in "$@"; do
        if "$toggle"; then
            toggle="false"
            if [[ $parameter =~ ^-[notepr]$ ]]; then
                compare="${parameter#-}"
                continue 
            fi
        fi
        toggle="true"
        while "true"; do
            eval local "patterns=($parameter)"
            if [[ ${#patterns[@]} -gt 0 ]]; then
                for pattern in "${patterns[@]}"; do
                    [[ i -lt ${#common_messages[@]} ]] || break
                    if [[ i -lt 0 ]]; then
                        value="$common_status"
                    else
                        value="${common_messages[i]}"
                    fi
                    case $compare in
                    [ne]) [[ ! $value == "$pattern" ]] || break 2;;
                    [op]) [[ ! $value == $pattern ]] || break 2;;
                    [tr]) [[ ! $value =~ $pattern ]] || break 2;;
                    esac
                done
            fi
            if [[ $compare == [not] ]]; then
                let "++i,1"
                continue 2
            else
                status="1"
                break 2
            fi
        done
        if [[ $compare == [not] ]]; then
            status="1"
            break
        else
            let "++i,1"
        fi
    done
    [[ $options == *f* ]] || set +f
    return "$status"
} 

common.hctaC() {
    common.TryCatchFinallyVerify || return
    common.TryCatchFinallyNext "[c]" "h" || return 
    [[ $# -ne 1 || $1 != -r ]] || common_status="0"
}

common.Finally() {
    common.TryCatchFinallyVerify || return
    common.TryCatchFinallyNext "[ych]" "f" || return 
}

common.yllaniF() {
    common.TryCatchFinallyVerify || return
    common.TryCatchFinallyNext "[f]" "l" || return 
    [[ common_status -eq 0 ]] || common.Throw
}

common.Caught() {
    common.TryCatchFinallyVerify || return
    [[ common_status -eq 0 ]] || return 1
}

common.EchoExitStatus() {
    return "${1:-$?}"
}

common.EnableThrowOnError() {
    common.TryCatchFinallyVerify || return
    [[ $common_options == *e* ]] || common_options+="e"
}

common.DisableThrowOnError() {
    common.TryCatchFinallyVerify || return
    common_options="${common_options/e}"
}

common.GetStatus() {
    common.TryCatchFinallyVerify || return
    echo "$common_status"
}

common.SetStatus() {
    common.TryCatchFinallyVerify || return
    if [[ $# -ne 1 ]]; then
        echo "$(common.GetAlias): $#: Wrong number of parameters" >&2
        return "1"         
    elif [[ ${#1} -gt 16 || -n ${1%%[0-9]*} || 10#$1 -lt 1 || 10#$1 -gt 255 ]]; then
        echo "$(common.GetAlias): $1: First parameter was not an integer between 1 and 255" >&2
        return "1"
    fi
    let "common_status = 10#$1"
}

common.GetMessage() {
    common.TryCatchFinallyVerify || return
    local "upper=${#common_messages[@]}"
    if [[ upper -eq 0 ]]; then
        echo "$(common.GetAlias): $1: There are no messages" >&2
        return "1"
    elif [[ $# -ne 1 ]]; then
        echo "$(common.GetAlias): $#: Wrong number of parameters" >&2
        return "1"         
    elif [[ ${#1} -gt 16 || -n ${1%%[0-9]*} || 10#$1 -ge upper ]]; then
        echo "$(common.GetAlias): $1: First parameter was an invalid index" >&2
        return "1"
    fi
    echo "${common_messages[$1]}"
}

common.MessageCount() {
    common.TryCatchFinallyVerify || return
    echo "${#common_messages[@]}"
}

common.CopyMessages() {
    common.TryCatchFinallyVerify || return
    if [[ $# -ne 1 ]]; then
        echo "$(common.GetAlias): $#: Wrong number of parameters" >&2
        return "1"         
    elif [[ ${#common_messages} -gt 0 ]]; then
        eval "$1=(\"\${common_messages[@]}\")"
    else
        eval "$1=()"
    fi
}

common.TryCatchFinallyExists() {
    [[ ${common_fifo:-u} != u ]]
}

common.TryCatchFinallyVerify() {
    local "name"
    if ! common.TryCatchFinallyExists; then
        echo "$(common.GetAlias "1"): No Try-Catch-Finally exists" >&2
        return "2"        
    fi
}

common.GetOptions() {
    local "opt"
    local "name=$(common.GetAlias "1")"
    if common.TryCatchFinallyExists; then
        echo "$name: A Try-Catch-Finally already exists" >&2
        return "1"        
    fi
    let "OPTIND = 1"
    let "OPTERR = 0"
    while getopts ":cdeh:ko:u:v:" opt "$@"; do
        case $opt in
        c)  [[ $common_options == *c* ]] || common_options+="c";;
        d)  [[ $common_options == *d* ]] || common_options+="d";;
        e)  [[ $common_options == *e* ]] || common_options+="e";;
        h)  common_errHandler="$OPTARG";;
        k)  [[ $common_options == *k* ]] || common_options+="k";;
        o)  common_file="$OPTARG";;
        u)  common_unhandled="$OPTARG";;
        v)  common_command="$OPTARG";;
        \?) #echo "Invalid option: -$OPTARG" >&2
            echo "$name: Illegal option: $OPTARG" >&2
            return "1";;
        :)  echo "$name: Option requires an argument: $OPTARG" >&2
            return "1";;
        *)  echo "$name: An error occurred while parsing options." >&2
            return "1";;
        esac
    done

    shift "$((OPTIND - 1))"
    if [[ $# -lt 1 ]]; then
        echo "$name: The fifo_file parameter is missing" >&2
        return "1"
    fi
    common_fifo="$1"
    if [[ ! -p $common_fifo ]]; then
        echo "$name: $1: The fifo_file is not an open FIFO" >&2
        return "1"  
    fi

    shift
    if [[ $# -lt 1 ]]; then
        echo "$name: The function parameter is missing" >&2
        return "1"
    fi
    common_function="$1"
    if ! chmod "0600" "$common_fifo"; then
        echo "$name: $common_fifo: Can not change file mode to 0600" >&2
        return "1"
    fi

    local "message=" "eof=TRY_CATCH_FINALLY_END_OF_FILE_$RANDOM"
    { echo "$eof" >"$common_fifo"; } 2>"/dev/null"
    if [[ $? -ne 0 ]]; then
        echo "$name: $common_fifo: Can not write" >&2
        return "1"
    fi   
    { while [[ $message != *$eof ]]; do
        read "message"
    done <"$common_fifo"; } 2>"/dev/null"
    if [[ $? -ne 0 ]]; then
        echo "$name: $common_fifo: Can not read" >&2
        return "1"
    fi   

    return "0"
}

common.DefaultUnhandled() {
    local -i "i"
    echo "-------------------------------------------------"
    echo "$(common.GetAlias "common.TryCatchFinally"): Unhandeled exception occurred"
    echo "Status: $(GetStatus)"
    echo "Messages:"
    for ((i=0; i<$(MessageCount); i++)); do
        echo "$(GetMessage "$i")"
    done
    echo "-------------------------------------------------"
}

common.TryCatchFinally() {
    local "common_file=/dev/fd/2"
    local "common_errHandler=common.DefaultErrHandler"
    local "common_unhandled=common.DefaultUnhandled"
    local "common_options="
    local "common_fifo="
    local "common_function="
    local "common_flags=$-"
    local "common_trySubshell=-1"
    local "common_initSubshell=-1"
    local "common_subshell"
    local "common_status=0"
    local "common_order=b"
    local "common_command="
    local "common_messages=()"
    local "common_handler=$(trap -p ERR)"
    [[ -n $common_handler ]] || common_handler="trap ERR"

    common.GetOptions "$@" || return "$?"
    shift "$((OPTIND + 1))"

    [[ -z $common_command ]] || common_command+="=$"
    common_command+='("$common_function" "$@")'

    set -E
    set +e
    trap "common.ErrHandler" ERR
    if true; then
        common.Try 
        eval "$common_command"
        common.EchoExitStatus
        common.yrT
    fi
    while common.Catch; do
        "$common_unhandled" >&2
        break
        common.hctaC -r
    done
    common.hctaC
    [[ $common_flags == *E* ]] || set +E
    [[ $common_flags != *e* ]] || set -e
    [[ $common_flags != *f* || $- == *f* ]] || set -f
    [[ $common_flags == *f* || $- != *f* ]] || set +f
    eval "$common_handler"
    return "$((common_status?2:0))"
}

Bash中是否有TRY CATCH命令

13 个答案:

trycatch.sh