bash - 脚本中详细模式的优雅方式？

Question

当我编写 bash 脚本时，我通常以这种方式获得详细模式（简化）：

_V=0

while getopts "v" OPTION
do
  case $OPTION in
    v) _V=1
       ;;
  esac
done

然后每次我想要“详细输出”时，我都会输入：

[ $_V -eq 1 ] && echo "verbose mode on" || echo "verbose mode off"

或者例如这个：

[ $_V -eq 1 ] && command -v || command

有没有办法让它更优雅？我正在考虑定义一个名为“verbose”的函数并键入它而不是[ $_V -eq 1 ]，但这只是一个很小的改进。

我敢肯定，还有更常见的方法来做到这一点……</p>

score 43 · Accepted Answer

正如您所注意到的，您可以定义一些log函数，如log, log_debug,log_error等。

function log () {
    if [[ $_V -eq 1 ]]; then
        echo "$@"
    fi
}

它可以帮助增加您的主要代码可读性并将显示\非显示逻辑隐藏到日志功能中。

log "some text"

如果_V（全局变量）相等1，将打印“一些文本”，否则不会打印。

score 23 · Accepted Answer

在阅读了所有其他帖子后，我想出了这个

# set verbose level to info
__VERBOSE=6

declare -A LOG_LEVELS
# https://en.wikipedia.org/wiki/Syslog#Severity_level
LOG_LEVELS=([0]="emerg" [1]="alert" [2]="crit" [3]="err" [4]="warning" [5]="notice" [6]="info" [7]="debug")
function .log () {
  local LEVEL=${1}
  shift
  if [ ${__VERBOSE} -ge ${LEVEL} ]; then
    echo "[${LOG_LEVELS[$LEVEL]}]" "$@"
  fi
}

然后你可以像这样简单地使用它

# verbose error
.log 3 "Something is wrong here"

哪个会输出

[error] Something is wrong here

score 6 · Accepted Answer

#!/bin/bash
# A flexible verbosity redirection function
# John C. Petrucci (http://johncpetrucci.com)
# 2013-10-19
# Allows your script to accept varying levels of verbosity flags and give appropriate feedback via file descriptors.
# Example usage: ./this [-v[v[v]]]

verbosity=2 #Start counting at 2 so that any increase to this will result in a minimum of file descriptor 3.  You should leave this alone.
maxverbosity=5 #The highest verbosity we use / allow to be displayed.  Feel free to adjust.

while getopts ":v" opt; do
    case $opt in
        v) (( verbosity=verbosity+1 ))
        ;;
    esac
done
printf "%s %d\n" "Verbosity level set to:" "$verbosity"

for v in $(seq 3 $verbosity) #Start counting from 3 since 1 and 2 are standards (stdout/stderr).
do
    (( "$v" <= "$maxverbosity" )) && echo This would display $v 
    (( "$v" <= "$maxverbosity" )) && eval exec "$v>&2"  #Don't change anything higher than the maximum verbosity allowed.
done

for v in $(seq $(( verbosity+1 )) $maxverbosity ) #From the verbosity level one higher than requested, through the maximum;
do
    (( "$v" > "2" )) && echo This would not display $v 
    (( "$v" > "2" )) && eval exec "$v>/dev/null" #Redirect these to bitbucket, provided that they don't match stdout and stderr.
done

# Some confirmations:
printf "%s\n" "This message is seen at verbosity level 3 and above." >&3
printf "%s\n" "This message is seen at verbosity level 4 and above." >&4
printf "%s\n" "This message is seen at verbosity level 5 and above." >&5

score 2 · Accepted Answer

我还想出了这个函数来做一个快速的 ifelse：

function verbose () {
    [[ $_V -eq 1 ]] && return 0 || return 1
}

如果 $_V 设置为 1，这将执行一个命令。像这样使用它：

verbose && command #command will be executed if $_V == 1

或者

verbose && command -v || command # execute 'command -v' if $_V==1, else execute 'command'

score 2 · Accepted Answer

如果您想避免每次要记录某些内容时都执行“if”语句，您可以尝试这种方法（我就是这样做的）。

这个想法是log，你打电话$echoLog而不是打电话。因此，如果您处于详细模式，$echoLog将只是echo，但在非详细模式下，它是一个不打印任何内容并忽略参数的函数。

这是您可以复制的一些代码。

# Use `$echoLog` everywhere you print verbose logging messages to console
# By default, it is disabled and will be enabled with the `-v` or `--verbose` flags
declare echoLog='silentEcho'
function silentEcho() {
    :
}

# Somewhere else in your script's setup, do something like this
while [[ $# > 0 ]]; do
    case "$1" in
        -v|--verbose) echoLog='echo'; ;;
    esac
    shift;
done

现在，您可以$echoLog "Doing something verbose log worthy"随心所欲地放下线条。

score 1 · Accepted Answer

第一次尝试具有详细级别的更灵活的系统（Bash 4）：

# CONFIG SECTION
# verbosity level definitions
config[verb_levels]='debug info status warning error critical fatal'

# verbosity levels that are to be user-selectable (0-this value)
config[verb_override]=3

# user-selected verbosity levels (0=none, 1=warnings, 2=warnings+info, 3=warning+info+debug)
config[verbosity]=2

# FUNCTION DEFINITIONS SECTION
_messages() {
    # shortcut functions for messages
    # non overridable levels exit with errlevel
    # safe eval, it only uses two (namespaced) values, and a few builtins
    local verbosity macro level=0
    for verbosity in ${config[verb_levels]}; do
        IFS="" read -rd'' macro <<MACRO
        _$verbosity() {
            $( (( $level <= ${config[verb_override]} )) && echo "(( \${config[verbosity]} + $level > ${config[verb_override]} )) &&" ) echo "${verbosity}: \$@";
            $( (( $level > ${config[verb_override]} )) && echo "exit $(( level - ${config[verb_override]} ));" )
        }
MACRO
        eval "$macro"
        (( level++ ))
    done
}

# INITIALIZATION SECTION
_messages

初始化后，您可以在代码中的任何位置使用以下内容：

! (( $# )) && _error "parameter expected"

[[ -f somefile ]] && _warning "file $somefile already exists"

_info "some info"

_status "running command"
if (( ${config[verbosity]} <= 1 )); then
    command
else
    command -v
fi

# explicitly changing verbosity at run time
old_verbosity=${config[verbosity]}
config[verbosity]=1

等等

score 0 · Accepted Answer

verbose=false

while getopts "v" OPTION
do
  case $OPTION in
    v) verbose=true
       ;;
  esac
done

然后

$verbose && echo "Verbose mode on" || echo "Verbose mode off"

这将执行/bin/true or /bin/false，分别返回 0 或 1。

score 0 · Accepted Answer

为了避免使用多个 if 语句或使用变量来保存函数名，如何根据详细程度声明不同的函数！

这适用于所有 bourne shell 衍生产品，而不仅仅是 bash！

#verbose=verbose_true       # uncomment to make script verbose
if [ "$verbose" ]; then
  log() { echo "$@"; }
else
  log() { :; }
fi

log This Script is Verbose

注意：“verbose=verbose_true”的使用使脚本跟踪更好，但如果你愿意，你可以做一个。

score -1 · Accepted Answer

我会提出@fentas答案的修改版本：

# set verbose level to info
__VERBOSE=6

declare -A LOG_LEVELS
# https://en.wikipedia.org/wiki/Syslog#Severity_level
LOG_LEVELS=([0]="emerg" [1]="alert" [2]="crit" [3]="err" [4]="warning" [5]="notice" [6]="info" [7]="debug")
function .log () {
  local LEVEL=${1}
  shift
  if [ ${__VERBOSE} -ge ${LEVEL} ]; then
    if [ -t 0 ]; then
      # seems we are in an interactive shell
      echo "[${LOG_LEVELS[$LEVEL]}]" "$@" >&2
    else
      # seems we are in a cron job
      logger -p "${LOG_LEVELS[$LEVEL]}" -t "$0[$$]" -- "$*"
    fi
  fi
}

bash - 脚本中详细模式的优雅方式？

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