Unix Shell Programming Third Edition phần 4 pptx

... sticky area that is a frequent source of shell programming errors. It's good to really understand the principles here to save yourself a lot of programming headaches in the future. There ... are some sample uses of on: $ who root console Jul 8 10:37 barney tty03 Jul 8 12:38 fred tty 04 Jul 8 13 :40 joanne tty07 Jul 8 09:35 tony tty19 Jul 8 08:30 lulu tty23 Jul 8 09:55 3 c d e 2 d...

Ngày tải lên: 13/08/2014, 15:21

... continue, so continue n done becomes for i in 1 2 3 4; do echo $i; done And you can type it in directly this way: $ for i in 1 2 3 4; do echo $i; done 1 2 3 4 $ The same rules apply to while and until ... memo2 request id is laser1- 34 (standard input) $ run memo3 request id is laser1-35 (standard input) $ run memo4 request id is laser1-36 (standard input) $ Incidentally, the shell per...

Ngày tải lên: 13/08/2014, 15:21

... Bash shell beginning of line, matching 2nd bg command 2nd 3rd 4th 5th 6th books AWK Programming Language, The Learning Pearl Programming Pearl Unix C Shell Field Guide, The Unix in ... Shell Field Guide, The Unix in a Nutshell[colon] System V Edition Unix Programmer's Manual, Volume II Unix Programming Environment, The Bourne shell Bourne, S...

Ngày tải lên: 13/08/2014, 15:21

... Index Unix Shell Programming, Third Edition By Stephen G. Kochan, Patrick Wood Publisher : Sams Publishing Pub Date : February 27, 2003 ISBN : 0-672-3 249 0-3 Pages : 45 6 Slots : 1 Unix Shell Programming ... shell, such as bash. Three are covered in the third edition of Unix Shell Programming. It begins with a generalized tutorial of Unix and tools and then mov...

Ngày tải lên: 13/08/2014, 15:21

... occurrences of " ;Unix& quot; in the text to " ;UNIX. " This can be easily done in sed as follows: $ sed 's /Unix/ UNIX/' intro Substitute Unix with UNIX The UNIX operating system ... at the output from the who command: $ who root console Feb 24 08: 54 steve tty02 Feb 24 12:55 george tty08 Feb 24 09:15 dawn tty10 Feb 24 15:55 $ As shown, currently four people...

Ngày tải lên: 13/08/2014, 15:21

... "What Is the Shell? ," you should realize that whenever you type something like who | wc -l that you are actually programming in the shell! That's because the shell is interpreting ... into detail on the quoting mechanisms in the shell. Variables Like virtually all programming languages, the shell allows you to store values into variables. A shell variable begin...

Ngày tải lên: 13/08/2014, 15:21

... $number2 done $ cat data 12 34 7960 593 -595 395 3 04 32 34 999 -3 94 -49 3 $ align data 12 34 7960 593 -595 395 3 04 32 34 999 -3 94 -49 3 $ In Chapters 12, 14, and 15 you'll see more uses for printf. ... the subshell, whereas the list of local variables does not (see Figure 11 .4) . Figure 11 .4. Execution of vartest3. Now it's time for another question: What do you th...

Ngày tải lên: 13/08/2014, 15:21

... 2 and then execute a subshell, which in turn executes other shell programs as subshells. If an interrupt signal is then generated, it will have no effect on the shells or subshells that are executing ... sorted_data & Send it to the background [1] 342 3 Job number & process id from the shell $ date Do some other work Wed Oct 2 15:05 :42 EDT 2002 $ wait 342 3 Now wait for the sort...

Ngày tải lên: 13/08/2014, 15:21

... what shell to start up when you execute a shell escape. In such cases, you want to make sure that each time you start up a new shell, you get the shell you want and not an older Bourne shell. ... you to interactive features of the shell and two shells that have some nice features not found in the POSIX standard shell. Getting the Right Shell Most shells follow a convention...

Ngày tải lên: 13/08/2014, 15:21

... command-line option, or after set –o posix is executed. Table 15 .4. POSIX Shell, Korn Shell, and Bash Compatibility POSIX Shell Korn Shell Bash ENV file X X POS vi line edit mode X X X emacs ... Variables There are three different "types" of parameters: shell variables, special parameters, and positional parameters. Shell Variables A shell variable name must sta...

Ngày tải lên: 13/08/2014, 15:21