亚洲免费在线-亚洲免费在线播放-亚洲免费在线观看-亚洲免费在线观看视频-亚洲免费在线看-亚洲免费在线视频

Korn Shell(K Shell) Notes (I)

系統(tǒng) 2518 0

Korn Shell Notes

1 Useful Cmds

wc - display a count of lines, words and characters in a file.
It can be used to count the numbers together with other commands, such as ls, who and so on.

cut - cut out selected fields of each line of a file.
The name of each unique user that is logged on is displayed using this command:
$ who | cut —f1 —d' ' | sort —u
anatole
root

print is a Korn shellspecializedcommand which is similar to echo .

nl - line numbering filter.

2 Conditional Execution

You can implement a simple if command by using the && and || operators together like this:
command1 && command2 || command3
If command1 returns true, then command2 is executed, which causes command3 to not be executed. If command1 does not return true, then command2 is not executed, which causes command3 to be executed.

3 Grouping Commands

Commands enclosed in {} are executed in current shell. If
$ echo "This is file temp:" ; cat temp | nl
This is file temp:
1 The rain in Spain
2 falls mainly on the plain
then by using {}s, the output will be:
$ { echo "This is file temp:"; cat temp ; } | nl
1 This is file temp:
2 The rain in Spain
3 falls mainly on the plain
There must be whitespace after the opening {, and commands within the {}'s must be terminated with a semi-colon.

Commands enclosed in () are executed in a subshell. Subshells are generated whenever you enclose commands in ()'s, perform command substitution, for background processes, and for coprocesses.A subshell is a separate copy of the parent shell, so variables, functions, and aliases from the parent shell are available to the subshell. However, subshells cannot change the value of parent shell variables, functions, or aliases.

4 Redirecting Standard Output

By using the > symbol, the standard output of a command can be redirected to a file, instead of your terminal.

You can also use the > command to create an empty file:
$ > tmp
$ ls —s tmp
0 tmp
This is equivalent to touch tmp .

Standard output can be appended to a file by using the >> redirect operator.

Standard output is closed with the >&- redirect operator:
$ echo "This is going nowhere" >&-
$


Korn Shell(K Shell) Notes (I)


更多文章、技術(shù)交流、商務(wù)合作、聯(lián)系博主

微信掃碼或搜索:z360901061

微信掃一掃加我為好友

QQ號(hào)聯(lián)系: 360901061

您的支持是博主寫(xiě)作最大的動(dòng)力,如果您喜歡我的文章,感覺(jué)我的文章對(duì)您有幫助,請(qǐng)用微信掃描下面二維碼支持博主2元、5元、10元、20元等您想捐的金額吧,狠狠點(diǎn)擊下面給點(diǎn)支持吧,站長(zhǎng)非常感激您!手機(jī)微信長(zhǎng)按不能支付解決辦法:請(qǐng)將微信支付二維碼保存到相冊(cè),切換到微信,然后點(diǎn)擊微信右上角掃一掃功能,選擇支付二維碼完成支付。

【本文對(duì)您有幫助就好】

您的支持是博主寫(xiě)作最大的動(dòng)力,如果您喜歡我的文章,感覺(jué)我的文章對(duì)您有幫助,請(qǐng)用微信掃描上面二維碼支持博主2元、5元、10元、自定義金額等您想捐的金額吧,站長(zhǎng)會(huì)非常 感謝您的哦!!!

發(fā)表我的評(píng)論
最新評(píng)論 總共0條評(píng)論
主站蜘蛛池模板: 欧美精品aaa久久久影院 | 色最快国产 | 天天做天天爱天天一爽一毛片 | 日韩在线免费视频观看 | 亚洲毛片免费观看 | 动漫精品一区二区 | 国产成人亚洲精品久久 | 精品成人 | 青青青国产成人久久111网站 | 九九久久精品这里久久网 | 久久99精品久久久久久综合 | 亚洲国产清纯 | 国产成人一区二区三区精品久久 | 亚久久 | 免费a级网站| 亚洲国产精品一区二区不卡 | 一区在线播放 | 操熟美女又肥又嫩的骚屁股 | 在线观看 一区二区 麻豆 | 日日撸夜夜撸网站 | 久久噜噜噜 | 成人看片黄a免费 | 国产精品视频福利一区二区 | 欧美在线播放成人免费 | 国产三级不卡 | 色姑娘天天操 | 国产乱仑 | 亚洲精品国产一区二区三 | 日本高清有码 | a高清免费毛片久久 | 久久免费国产视频 | 久久97久久97精品免视看 | 一级做a爰片性色毛片2021 | 欧美激情在线观看一区二区三区 | 国产精品久久久久久久久久一区 | 日韩a级黄色片 | 久久青青草原精品影院 | 一 级 黄 色 片生活片 | 变态 调教 视频 国产九色 | 伊人五月 | 日本视频久久 |