03 2021 档案

How Linux Keeps Track of Time
摘要：A Linux system actually has two clocks: One is the battery powered "Real Time Clock" (also known as the "RTC", "CMOS clock", or "Hardware clock") whic 阅读全文
posted @ 2021-03-30 12:59 碧水东流至此回 阅读(69) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 18/n
摘要：CHAPTER 10|bash Administration Installing bash as the Standard Shell # cor@debian:~/shell/mar17$ cat 3.sh IFS=: for d in $PATH;do echo checking $d: cd 阅读全文
posted @ 2021-03-17 17:00 碧水东流至此回 阅读(86) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 17/n
摘要：CHAPTER 9|Debugging Shell Programs This chapter looks at some useful features that you can use to debug shell programs.We’ll look at how you can utili 阅读全文
posted @ 2021-03-16 15:44 碧水东流至此回 阅读(73) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 16/n
摘要：CHAPTER 8 Process Handling Process IDs and Job Numbers UNIX gives all processes numbers, called process IDs, when they are created. Job Control Foregr 阅读全文
posted @ 2021-03-15 15:30 碧水东流至此回 阅读(88) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 15/n
摘要：Command-Line Processing it separates lines into words, according to delimiters in the environment variable IFS; and it assigns the words to shell vari 阅读全文
posted @ 2021-03-10 09:30 碧水东流至此回 阅读(53) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 14/n
摘要：Chapter 7 Input/Output and Command-Line Processing I/O Redirectors The redirector <> is mainly meant for use with device files (in the /dev directory) 阅读全文
posted @ 2021-03-08 16:03 碧水东流至此回 阅读(92) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 13/n
摘要：Arithmetic Conditionals Operator Meaning -lt Less than -gt Greater than -le Less than or equal to -ge Greater than or equal to -eq Equal to -ne Not eq 阅读全文
posted @ 2021-03-08 13:34 碧水东流至此回 阅读(70) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 12/n
摘要：Typed Variables You can set variable attributes with the declare built-in. * Table 6-1 summarizes the available options with declare. Option Meaning - 阅读全文
posted @ 2021-03-08 11:17 碧水东流至此回 阅读(57) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 11/n
摘要：for|case|select|while and until Command-Line Options and Typed Variables Command-Line Options Typical UNIX commands have the form command [-options]ar 阅读全文
posted @ 2021-03-04 16:29 碧水东流至此回 阅读(66) 评论(1) 推荐(0)
Learning_the_bash_Shell_Third_Edition 10/n
摘要：Flow Control Exit Status Every UNIX command, whether it comes from source code in C, some other language, or a shell script/function, returns an integ 阅读全文
posted @ 2021-03-04 10:54 碧水东流至此回 阅读(87) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 9/n
摘要：Advanced Examples: pushd and popd Task 4-8 The functions pushd and popd implement a stack of directories that enable you to moveto another directory t 阅读全文
posted @ 2021-03-04 10:10 碧水东流至此回 阅读(55) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 8/n
摘要：Command Substitution The command inside the parentheses is run, and anything the command writes to standard output is returned as the value of the exp 阅读全文
posted @ 2021-03-03 18:01 碧水东流至此回 阅读(75) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 7/n(chapter 4, page[117|99])
摘要：Extended Pattern Matching Operator Meaning *(patternlist) Matches zero or more occurrences of the given patterns. +(patternlist) Matches one or more o 阅读全文
posted @ 2021-03-03 11:09 碧水东流至此回 阅读(56) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 6/n(chapter 4, page[117|99])
摘要：Length Operator(chapter 4, page[117|99]) There is one remaining operator on variables. It is ${#varname}, which returns the length of the value of the 阅读全文
posted @ 2021-03-03 11:08 碧水东流至此回 阅读(42) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 5/n
摘要：Patterns and Pattern Matching wildcard(通配符) Operator Meaning ${variable#pattern} If the pattern matches the beginning of the variable’s value, delete 阅读全文
posted @ 2021-03-03 10:47 碧水东流至此回 阅读(45) 评论(0) 推荐(0)
Learning_the_bash_Shell_Third_Edition 4.1/n(109|91)
摘要：To define a function, you can use either one of two forms: function functname{ shell commands} or: functname ( ) { shell commands} You can also delete 阅读全文
posted @ 2021-03-02 09:42 碧水东流至此回 阅读(113) 评论(0) 推荐(0)