scripts.ps

物业管理和办公自动化系统

0.11 ( is typed, a procedure called) 118.14 520.5 P
5 11 Q
0.11 (yes) 256.34 520.5 P
0 12 Q
0.11 ( is invoked.  This could further automate the) 273.43 520.5 P
2 F
0.11 (fsck) 490.26 520.5 P
0 F
0.11 ( inter-) 510.92 520.5 P
-0.25 (action just described, so that the user does not have to explicitly start the interpreter and type) 72 506.5 P
4 F
-0.6 (yes) 515.41 506.5 P
0 F
-0.25 (.) 537 506.5 P
4 F
0.35 (~a) 72 492.5 P
0 F
0.15 ( invokes a more complex action.  When typed,) 86.39 492.5 P
4 F
0.35 (hello world) 313.89 492.5 P
0 F
0.15 ( is seen at the terminal and the) 393.4 492.5 P
-0.21 (current date is sent to the process as if the user had typed it.  The other pairs exit or suspend an) 72 478.5 P
2 F
-0.21 (ex-) 524.68 478.5 P
0.92 (pect) 72 464.5 P
0 F
0.92 ( session while interacting with a spawned process.  \050W) 93.31 464.5 P
0.92 (ith no map, the characters would be) 363.6 464.5 P
-0.08 (passed uninterpreted to the current process.\051  Appropriate maps can simulate) 72 450.5 P
2 F
-0.08 (csh) 441.54 450.5 P
0 F
-0.08 (-style job control) 458.2 450.5 P
-0.14 (or much fancier actions.  For instance,) 72 436.5 P
5 11 Q
-0.14 (^Z) 257.9 436.5 P
0 12 Q
-0.14 ( could pass control to the interactive) 269.77 436.5 P
2 F
-0.14 (expect) 445.69 436.5 P
0 F
-0.14 ( interpreter \320) 478.33 436.5 P
-0.14 (analogous to what) 72 422.5 P
5 11 Q
-0.15 (^Z) 161.84 422.5 P
0 12 Q
-0.14 ( does in the shell \320 or it could change jobs to a spawned shell and resume the) 173.71 422.5 P
(interaction.) 72 408.5 T
0.36 (An unrealistic but amusing application of character mapping is the following script which runs a) 72 384.5 P
(shell with a Dvorak keyboard.  For brevity) 72 370.5 T
(, only lowercase letters are mapped.) 275.74 370.5 T
4 F
(proc dvorak {} {) 115.2 337 T
(interact ~q {return continue} ~d {} \134) 162 323.5 T
(q {send \325} w {send ,} e {send .} \134) 207 310 T
(r {send p} t {send y} y {send f} \134) 207 296.5 T
(u {send g} i {send c} o {send r} \134) 207 283 T
(p {send l} s {send o} d {send e} \134) 207 269.5 T
(f {send u} g {send i} h {send d} \134) 207 256 T
(j {send h} k {send t} l {send n} \134) 207 242.5 T
(x {send q} c {send j} v {send k} \134) 207 229 T
(b {send x} n {send b} , {send w} \134) 207 215.5 T
(. {send v} / {send z} \325 {send -} \134) 207 202 T
(\134; {send s} z {send \134;} \134) 207 188.5 T
(}) 115.2 175 T
(log_user 0) 115.2 148 T
(scan [exec printenv SHELL] "%s" shell) 115.2 134.5 T
(spawn $shell) 115.2 121 T
(log_user 1) 115.2 107.5 T
(send_user "~d for dvorak, ~q for qwerty \050default\051\134n") 115.2 94 T
(send_user "Enter ~ sequences using qwerty keys\134n") 115.2 80.5 T
(interact ~d dvorak ~q {}) 115.2 67 T
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(expect: Scripts for Controlling Interactive Processes) 295.54 39.95 T
0 12 Q
(13) 528.01 39.95 T
72 63 540 720 R
7 X
V
0 X
0.47 (Once the timeout is set and the program is spawned,) 72 712 P
5 11 Q
0.48 (expect) 330.17 712 P
0 12 Q
0.47 ( waits for either an end-of-\336le or the) 362.53 712 P
0.61 (20 seconds to pass.  If the end-of-\336le is seen, the program has \050almost certainly\051 exited, and) 72 698 P
5 11 Q
0.62 (ex-) 524.74 698 P
-0.11 (pect) 72 684 P
0 12 Q
-0.11 ( returns.  If the timeout has passed,) 92.76 684 P
5 11 Q
-0.11 (expect) 262.44 684 P
0 12 Q
-0.11 ( returns.  In either case) 294.81 684 P
2 F
-0.11 (expect) 406.39 684 P
0 F
-0.11 ( exits, implicitly kill-) 439.03 684 P
(ing the current process.) 72 670 T
0.05 (It is educational to try and solve these last two examples without using) 72 646 P
2 F
0.05 (expect) 414.83 646 P
0 F
0.05 (.  In both cases, the) 447.46 646 P
0.78 (usual approach is to fork a second process that sleeps and then signals the original shell.  If the) 72 632 P
1.23 (process or read \336nishes \336rst, the shell kills the sleeper) 72 618 P
1.23 (.  Passing pids and preventing the back-) 340.87 618 P
0.33 (ground process start message is a stumbling block for all but the most expert shell programmers.) 72 604 P
0.56 (Providing a general approach to starting multiple processes this way complicates the shell script) 72 590 P
(immensely) 72 576 T
(.  Invariably) 123.86 576 T
(, the programmer writes a special-purpose C program.) 181.37 576 T
5 11 Q
0.2 (expect_user) 72 552 P
0 12 Q
0.2 (,) 131.36 552 P
5 11 Q
0.2 (send_user) 137.56 552 P
0 12 Q
0.2 (, and) 188.38 552 P
5 11 Q
0.2 (send_error) 215.09 552 P
0 12 Q
0.2 ( \050for writing to the standard error\051 are frequently used in) 268.21 552 P
0.02 (longer) 72 538 P
2 F
0.02 (expect) 105.66 538 P
0 F
0.02 ( scripts which translate a complex interaction from a process to a simple one for the) 138.3 538 P
0.29 (user) 72 524 P
0.29 (.  In [7], Libes describes how) 91.32 524 P
2 F
0.29 (adb) 236.27 524 P
0 F
0.29 ( could be securely wrapped with a script, preventing a sys-) 255.6 524 P
0.38 (tem administrator from needing to master the intricacies of) 72 510 P
2 F
0.38 (adb) 360.85 510 P
0 F
0.38 (, while at the same time dramati-) 380.19 510 P
(cally lessening the likelihood of a system crash due to an errant keystroke.) 72 496 T
-0.24 (A simpler example is automating) 72 472 P
2 F
-0.24 (ftp) 233.03 472 P
0 F
-0.24 ( to retrieve \336les from a personal account.  In this case, a pass-) 247.69 472 P
0.18 (word must be supplied.  Storing the cleartext password in a \336le should be avoided even if the \336le) 72 458 P
-0.19 (permissions are heavily restricted.  Supplying passwords as ar) 72 444 P
-0.19 (guments to a script is also a security) 367.75 444 P
0.04 (risk due to the ability of) 72 430 P
2 F
0.04 (ps) 190.15 430 P
0 F
0.04 ( to retrieve them.  A solution is to call) 201.48 430 P
5 11 Q
0.04 (expect_user) 386.74 430 P
0 12 Q
0.04 ( at the beginning of) 446.58 430 P
0.57 (the script for each password that the script must supply later) 72 416 P
0.57 (.  The password will be available to) 365.48 416 P
(the script \050and only to the script\051, even if it has to retry) 72 402 T
2 F
(ftp) 337.15 402 T
0 F
( every hour) 351.81 402 T
(.) 405.77 402 T
0.57 (This technique is useful even if the information is to be entered immediately) 72 378 P
0.57 (.  For example, you) 444.46 378 P
-0.08 (can write a script which changes your password on every machine on which you have an account,) 72 364 P
0.44 (whether or not the machines share a common password database \050or even run UNIX\051.  By hand,) 72 350 P
-0.1 (you might have to) 72 336 P
2 F
-0.1 (telnet) 161.54 336 P
0 F
-0.1 ( to each machine and then enter the new password.  W) 190.18 336 P
-0.1 (ith) 449.71 336 P
2 F
-0.1 (expect) 465.27 336 P
0 F
-0.1 (, you en-) 497.9 336 P
(ter the password once and let the script do the rest of the work.) 72 322 T
5 11 Q
0.17 (expect_user) 72 298 P
0 12 Q
0.17 ( and) 131.84 298 P
5 11 Q
0.17 (interact) 155.5 298 P
0 12 Q
0.17 ( can also be mixed in a single script.  Imagine debugging a program that) 191.52 298 P
1.63 (only fails after many iterations of a loop.  An) 72 284 P
2 F
1.63 (expect) 307.84 284 P
0 F
1.63 ( script could drive the debugger) 340.48 284 P
1.63 (, setting) 500.38 284 P
0.2 (breakpoints, running the program for the appropriate number of loops, and then returning control) 72 270 P
-0.19 (to the keyboard.  It could also alternate between looping and testing for a condition, before return-) 72 256 P
(ing control.) 72 242 T
3 16 Q
(10.  Programming expect interactively) 108 201.33 T
2 12 Q
1.2 (expect) 72 176 P
0 F
1.2 ( may be programmed interactively) 104.63 176 P
1.2 (.  For example, if) 273.86 176 P
2 F
1.2 (expect) 365.46 176 P
0 F
1.2 ( is run with no ar) 398.1 176 P
1.2 (guments, it) 485.49 176 P
1.31 (prompts for commands.  This is similar to what one normally does when interactively using a) 72 162 P
-0.12 (shell.  This interactive mode may also be entered by pressing a user) 72 148 P
-0.12 (-de\336ned string during) 394.41 148 P
5 11 Q
-0.12 (interact) 500.98 148 P
0 12 Q
-0.12 (.) 537 148 P
-0.19 (Once prompted by the interpreter) 72 124 P
-0.19 (, you can type) 230.63 124 P
2 F
-0.19 (expect) 300.15 124 P
0 F
-0.19 ( commands which are executed immediate-) 332.78 124 P
-0.07 (ly) 72 110 P
-0.07 (.  Y) 80.55 110 P
-0.07 (ou can call de\336ned procedures, perform job control, or even recursively invoke) 96.88 110 P
5 11 Q
-0.07 (interact) 478.45 110 P
0 12 Q
-0.07 (.  For) 514.48 110 P
0.64 (example, suppose you are running a script to automate) 72 96 P
2 F
0.64 (fsck) 342.21 96 P
0 F
0.64 (.  Y) 362.86 96 P
0.64 (ou answer some of the questions) 380.59 96 P
-0.13 (yourself, and then decide that the rest should all be answered \322yes\323.  Y) 72 82 P
-0.13 (ou can escape from) 408.57 82 P
5 11 Q
-0.13 (interact) 503.98 82 P
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(12) 72 39.95 T
0 10 Q
(Don Libes) 108 39.95 T
72 740.81 504 756 R
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72 63 540 720 R
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0 12 Q
0 X
0.81 (a) 72 712 P
5 11 Q
0.82 (^Z) 81.13 712 P
0 12 Q
0.81 (, the process stops and control returns to the shell.  As far as) 92.99 712 P
2 F
0.81 (expect) 395.4 712 P
0 F
0.81 ( is concerned, it is still) 428.03 712 P
(dealing with the same process \050the original shell\051.) 72 698 T
0.64 (Not only is) 72 674 P
2 F
0.64 (expect) 130.23 674 P
0 F
0.64 (\325) 162.87 674 P
0.64 (s approach \337exible, it also avoids duplicating the job control software that is) 166.2 674 P
0.15 (already in the shell.  By using the shell, you get the job control of your choice since you can pick) 72 660 P
-0.05 (the shell to spawn.  And should you need to \050such as when testing\051, you really can drive a shell so) 72 646 P
0.08 (that it thinks it is running interactively) 72 632 P
0.08 (.  This is also useful for programs that change the way they) 255.6 632 P
(buf) 72 618 T
(fer output after detecting whether they are running interactively or not.) 87.77 618 T
0.56 (T) 72 594 P
0.56 (o further pin things down, during) 78.49 594 P
5 11 Q
0.56 (interact) 244.05 594 P
0 12 Q
0.56 (,) 280.08 594 P
2 F
0.56 (expect) 286.63 594 P
0 F
0.56 ( puts the controlling terminal \050the one) 319.26 594 P
2 F
0.56 (expect) 507.37 594 P
0 F
0.53 (was invoked from, not the pty\051 into raw mode so that all characters pass to the spawned process) 72 580 P
0.54 (verbatim.  When) 72 566 P
2 F
0.54 (expect) 156.88 566 P
0 F
0.54 ( is not executing) 189.52 566 P
5 11 Q
0.55 (interact) 273.62 566 P
0 12 Q
0.54 (, the terminal is in cooked mode, at which time) 309.64 566 P
(shell job control can be used on) 72 552 T
2 F
(expect) 226.9 552 T
0 F
( itself.) 259.53 552 T
3 16 Q
(9.  Using expect interactively) 108 511.33 T
0 12 Q
1.09 (Earlier were shown scripts that are used interactively with) 72 486 P
5 11 Q
1.11 (interact) 363.24 486 P
0 12 Q
1.09 (.) 399.27 486 P
5 11 Q
1.11 (interact) 410.44 486 P
0 12 Q
1.09 ( essentially gives a) 446.46 486 P
-0.07 (user free access to the dialogue, but sometimes \336ner control is desired.    This can be achieved us-) 72 472 P
-0.12 (ing) 72 458 P
5 11 Q
-0.12 (expect) 90.21 458 P
0 12 Q
-0.12 ( which can read from the standard input just as easily as it reads from a process.  A pre-) 122.57 458 P
3.56 (de\336ned) 72 444 P
5 11 Q
3.63 (spawn_id) 113.87 444 P
0 12 Q
3.56 ( maps to the standard input and the standard output.  Alternatively) 160.27 444 P
3.56 (, the) 515.79 444 P
0.06 (commands) 72 430 P
5 11 Q
0.06 (expect_user) 127.03 430 P
0 12 Q
0.06 ( and) 186.87 430 P
5 11 Q
0.06 (send_user) 210.3 430 P
0 12 Q
0.06 ( perform I/O with the standard input and the standard out-) 261.6 430 P
(put without changing) 72 416 T
5 11 Q
(spawn_id) 176.94 416 T
0 12 Q
(.) 223.35 416 T
0.33 (The following script reads a line from the standard input for a given amount of time.  This script) 72 392 P
2.87 (\050named) 72 378 P
2 F
2.87 (timed_r) 113.83 378 P
2.87 (ead) 154.25 378 P
0 F
2.87 (\051 can be called from, for example, a) 172.24 378 P
2 F
2.87 (csh) 369.01 378 P
0 F
2.87 ( script as) 385.66 378 P
4 F
6.88 (set answer =) 439.89 378 P
(\324time) 72 364 T
(d_read 30\324) 107.98 364 T
0 F
(.) 179.94 364 T
4 F
(#!/usr/local/bin/expect -f) 115.2 344 T
(set timeout [index $argv 1]) 115.2 330.5 T
(expect_user "*\134n") 115.2 317 T
(send_user $expect_match) 115.2 303.5 T
0 F
0.96 (The third line accepts any newline-terminated line from the user) 72 280 P
0.96 (.  The last line returns it to the) 388.08 280 P
(standard output.  If nothing is typed before the timeout, nothing is returned.) 72 266 T
-0.22 (The \336rst line allows systems that support the) 72 242 P
5 11 Q
-0.23 (#!) 287.43 242 P
0 12 Q
-0.22 ( magic to invoke the script directly \050without saying) 296.6 242 P
4 F
-0.44 (expect) 72 228 P
0 F
-0.19 ( before the script name\051 if its execute permission is set.   Of course a script can always be) 115.18 228 P
-0.07 (invoked explicitly) 72 214 P
-0.07 (, as) 158.1 214 P
4 F
-0.17 (\322expect script\323) 176.95 214 P
0 F
-0.07 (.  Options preceded by a) 284.72 214 P
5 11 Q
-0.07 (\320c) 403.86 214 P
0 12 Q
-0.07 ( \337ag are executed as com-) 415.47 214 P
0.28 (mands before any in the script.  For example, an) 72 200 P
2 F
0.28 (expect) 309.25 200 P
0 F
0.28 ( script can be traced without reediting by) 341.88 200 P
0.59 (invoking it as) 72 186 P
4 F
1.42 (expect -c "trace ..." script) 142.08 186 P
0 F
0.59 ( \050where the ellipsis represents a tracing) 349.26 186 P
(option\051.) 72 172 T
0.42 (Multiple commands may be strung together on a single script line or within braces, separated by) 72 148 P
0.79 (semi-colons.  Naturally) 72 134 P
0.79 (, this extends to the) 185.05 134 P
5 11 Q
0.8 (\320c) 284.93 134 P
0 12 Q
0.79 ( ar) 296.53 134 P
0.79 (gument.  For example, the following command) 309.42 134 P
(runs program) 72 120 T
2 F
(foo) 139.28 120 T
0 F
( for 20 seconds.) 155.27 120 T
4 F
(expect -c "set timeout 20; spawn foo; expect") 115.2 100 T
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72 36 540 47.95 R
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(expect: Scripts for Controlling Interactive Processes) 295.54 39.95 T
0 12 Q
(11) 528.01 39.95 T
72 63 540 720 R
7 X
V
4 F
0 X
(case $tty in $ready {) 162 712 T
(set spawn_id $tty) 207 698.5 T
(expect "*\134r*" {) 207 685 T
(if $log {) 297 671.5 T
(send_user $expect_match) 342 658 T
(set log 0) 342 644.5 T
(}) 297 631 T
(} "*") 207 617.5 T
(if $log {) 207 604 T
(send_user $expect_match) 252 590.5 T
(}) 207 577 T
(set spawn_id $login; send $expect_match) 207 563.5 T
(}) 162 550 T
(}) 115.2 536.5 T
0 F
0.28 (The script works as follows.  First connections are made to a) 72 513 P
2 F
0.28 (login) 369.45 513 P
0 F
0.28 ( process and terminal.  By de-) 394.78 513 P
-0.02 (fault, an entire session is logged to the standard output \050via) 72 499 P
5 11 Q
-0.02 (send_user) 357.59 499 P
0 12 Q
-0.02 (\051.  Since this is not of inter-) 408.89 499 P
1.61 (est, it is disabled by the command) 72 485 P
4 F
3.86 (log_user 0) 249.15 485 P
0 F
1.61 (.  \050A variety of commands are available to) 324.97 485 P
(control exactly what is seen or logged.\051) 72 471 T
1.05 (In a loop,) 72 447 P
5 11 Q
1.07 (select) 123.79 447 P
0 10 Q
0.88 (3) 152.49 451.8 P
0 12 Q
1.05 ( waits for activity from either the terminal or the process and returns a list of) 157.48 447 P
5 11 Q
0 (spawn_id) 72 43