bash bash_aliases 和 awk 转义引号
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bash_aliases and awk escaping of quotes
提问by Massagran
I'm trying to create an alias for a command to see the memory use,
我正在尝试为命令创建别名以查看内存使用情况，
ps -u user -o rss,command | grep -v peruser | awk '{sum+=} END {print sum/1024}'
but, the naive,
但是，天真，
#.bash_aliases
alias totalmem='ps -u user -o rss,command | grep -v peruser | awk '{sum+=} END {print sum/1024}''
gives errors:
给出错误：
-bash: alias: END: not found
-bash: alias: {print: not found
-bash: alias: sum/1024}: not found
I've tried with double quotes,
我试过用双引号，
totalmem ="ps ... |awk '{sum+=$1} END {print sum/1024}'", or
totalmem ="ps ... |awk '{sum+=$1} END {print sum/1024}'"， 或者
totalmem ='ps ... |awk "{sum+=$1} END {print sum/1024}"',
escaping,
totalmem ='ps ... |awk "{sum+=$1} END {print sum/1024}"', 逃脱,
totalmem ='ps ... |awk \'{sum+=$1} END {print sum/1024}\'',
or escaping double quotes ... but I can't seem to make it work.
totalmem ='ps ... |awk \'{sum+=$1} END {print sum/1024}\''，或转义双引号......但我似乎无法让它工作。
totalmem ='ps ... |awk \"{sum+=$1} END {print sum/1024}\"',
totalmem ='ps ... |awk \"{sum+=$1} END {print sum/1024}\"',
gives the error
给出错误
awk: "{sum+=}
awk: ^ unterminated string
Any tips appreciated.
任何提示表示赞赏。
回答by chepner
You can avoid quoting issues by using a shell function instead of an alias:
您可以通过使用 shell 函数而不是别名来避免引用问题：
totalmem () {
ps -u user -o rss,command | grep -v peruser | awk '{sum+=} END {print sum/1024}'
}
This is also more flexible, as you could allow totalmemto take arguments, such as a user name to pass to the -uoption of ps, as in this example:
这也更灵活，因为您可以允许totalmem采用参数，例如传递给-u选项的用户名ps，如下例所示：
totalmem () {
ps -u "" -o rss,command | grep -v peruser | awk '{sum+=} END {print sum/1024}'
}
回答by Thor
You almost have it, the $will be expanded in double-quotes, so that needs extra escaping:
你几乎拥有它，$将用双引号扩展，所以需要额外的转义：
alias totalmem='ps -u user -o rss,command | grep -v peruser | awk "{sum+=$1} END {print sum/1024}"'
Or with the pattern inside awkas suggested by iiSeymour:
或者awk按照iiSeymour 的建议使用内部模式：
alias totalmem='ps -u user -o rss,command | awk "!/peruser/ {sum+=$1} END {print sum/1024}"'
回答by Anton Kovalenko
Like this:
像这样：
alias totalmem='ps -u user -o rss,command | grep -v peruser | awk '\''{sum+=} END {print sum/1024}'\'
Explanation: you may use different kind of quotes for the same argument, like "I'm double-quoted"'and I am $HOME-less'-and-i-am-not-quoted. Hence if you need a single quote inside single quotes, you can add '\''which (1) terminates single quoting, (2) adds literal single quote with \', (3) starts single quoting again.
说明：您可以对同一个参数使用不同类型的引号，例如"I'm double-quoted"'and I am $HOME-less'-and-i-am-not-quoted. 因此，如果您需要单引号内的单引号，您可以添加'\''which (1) 终止单引号，(2) 添加文字单引号\'， (3) 再次开始单引号。
(Aliases of this size are something that's better done as functions).
（这种大小的别名最好作为函数来完成）。
