1AUTOEXPECT(1)               General Commands Manual              AUTOEXPECT(1)
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NAME

6       autoexpect - generate an Expect script from watching a session
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SYNOPSIS

9       autoexpect [ args ] [ program args...  ]
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INTRODUCTION

12       autoexpect  watches you interacting with another program and creates an
13       Expect script that  reproduces  your  interactions.   For  straightline
14       scripts,  autoexpect  saves  substantial  time  over writing scripts by
15       hand.  Even if you are an Expect expert, you will find it convenient to
16       use autoexpect to automate the more mindless parts of interactions.  It
17       is much easier to cut/paste hunks of autoexpect scripts  together  than
18       to write them from scratch.  And if you are a beginner, you may be able
19       to get away with learning nothing more about Expect than  how  to  call
20       autoexpect.
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22       The  simplest way to use autoexpect is to call it from the command line
23       with no arguments.  For example:
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25            % autoexpect
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27       By default, autoexpect spawns a shell for you.  Given  a  program  name
28       and arguments, autoexpect spawns that program.  For example:
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30            % autoexpect ftp ftp.cme.nist.gov
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32       Once your spawned program is running, interact normally.  When you have
33       exited the shell (or program that you specified), autoexpect will  cre‐
34       ate a new script for you.  By default, autoexpect writes the new script
35       to "script.exp".  You can override this with the -f flag followed by  a
36       new script name.
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38       The  following  example  runs  "ftp  ftp.cme.nist.gov"  and  stores the
39       resulting Expect script in the file "nist".
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41            % autoexpect -f nist ftp ftp.cme.nist.gov
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43       It is important to understand that  autoexpect  does  not  guarantee  a
44       working script because it necessarily has to guess about certain things
45       - and occasionally it guesses wrong.  However, it is usually very  easy
46       to identify and fix these problems.  The typical problems are:
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48              ·   Timing.   A  surprisingly large number of programs (rn, ksh,
49                  zsh, telnet, etc.) and devices (e.g.,  modems)  ignore  key‐
50                  strokes  that  arrive  "too  quickly" after prompts.  If you
51                  find your new script hanging up at one spot,  try  adding  a
52                  short sleep just before the previous send.
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54                  You  can  force  this  behavior throughout by overriding the
55                  variable "force_conservative" near the beginning of the gen‐
56                  erated  script.   This  "conservative" mode makes autoexpect
57                  automatically pause briefly (one tenth of a  second)  before
58                  sending  each character.  This pacifies every program I know
59                  of.
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61                  This conservative mode is useful if you just want to quickly
62                  reassure  yourself  that  the problem is a timing one (or if
63                  you really don't care about how fast the script runs).  This
64                  same  mode  can  be forced before script generation by using
65                  the -c flag.
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67                  Fortunately, these timing spots are rare.  For example, tel‐
68                  net  ignores  characters  only  after  entering  its  escape
69                  sequence.  Modems only ignore characters  immediately  after
70                  connecting  to  them  for  the  first  time.  A few programs
71                  exhibit this behavior all the  time  but  typically  have  a
72                  switch  to  disable  it.  For example, rn's -T flag disables
73                  this behavior.
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75                  The following  example  starts  autoexpect  in  conservative
76                  mode.
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78                       autoexpect -c
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80                  The  -C flag defines a key to toggle conservative mode.  The
81                  following example  starts  autoexpect  (in  non-conservative
82                  mode)  with  ^L as the toggle.  (Note that the ^L is entered
83                  literally - i.e., enter a real control-L).
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85                       autoexpect -C ^L
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87                  The following example starts autoexpect in conservative mode
88                  with ^L as the toggle.
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90                       autoexpect -c -C ^L
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93              ·   Echoing.  Many program echo characters.  For example, if you
94                  type "more" to a shell, what autoexpect actually sees is:
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96                       you typed 'm',
97                       computer typed 'm',
98                       you typed 'o',
99                       computer typed 'o',
100                       you typed 'r',
101                       computer typed 'r',
102                       ...
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104                  Without specific knowledge of the program, it is  impossible
105                  to  know  if  you  are  waiting to see each character echoed
106                  before typing the next.  If autoexpect sees characters being
107                  echoed,  it  assumes  that  it  can send them all as a group
108                  rather  than  interleaving  them  the  way  they  originally
109                  appeared.   This  makes  the  script  more pleasant to read.
110                  However, it could conceivably be incorrect if you really had
111                  to wait to see each character echoed.
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114              ·   Change.   Autoexpect records every character from the inter‐
115                  action in the script.  This is desirable  because  it  gives
116                  you  the  ability to make judgements about what is important
117                  and what can be replaced with a pattern match.
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119                  On the other hand, if you use commands whose output  differs
120                  from  run  to run, the generated scripts are not going to be
121                  correct.  For example, the "date"  command  always  produces
122                  different  output.   So using the date command while running
123                  autoexpect is a sure way  to  produce  a  script  that  will
124                  require editing in order for it to work.
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126                  The  -p  flag  puts  autoexpect into "prompt mode".  In this
127                  mode, autoexpect will only look for the last line of program
128                  output - which is usually the prompt.  This handles the date
129                  problem (see above) and most others.
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131                  The following example starts autoexpect in prompt mode.
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133                       autoexpect -p
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135                  The -P flag defines a key to toggle prompt mode.   The  fol‐
136                  lowing  example  starts autoexpect (in non-prompt mode) with
137                  ^P as the toggle.  Note that the ^P is entered  literally  -
138                  i.e., enter a real control-P.
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140                       autoexpect -P ^P
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142                  The  following example starts autoexpect in prompt mode with
143                  ^P as the toggle.
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145                       autoexpect -p -P ^P
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OTHER FLAGS

149       The -quiet flag disables informational messages produced by autoexpect.
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151       The -Q flag names a quote character which can be used to enter  charac‐
152       ters  that  autoexpect would otherwise consume because they are used as
153       toggles.
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155       The following example shows a number of flags with quote used  to  pro‐
156       vide a way of entering the toggles literally.
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158            autoexpect -P ^P -C ^L -Q ^Q
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160

STYLE

162       I  don't  know if there is a "style" for Expect programs but autoexpect
163       should definitely not be held up as any model of style.   For  example,
164       autoexpect  uses  features of Expect that are intended specifically for
165       computer-generated scripting.  So don't try to faithfully write scripts
166       that  appear as if they were generated by autoexpect.  This is not use‐
167       ful.
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169       On the other hand, autoexpect scripts do show some  worthwhile  things.
170       For  example, you can see how any string must be quoted in order to use
171       it in a Tcl script simply by running the strings through autoexpect.
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173

SEE ALSO

175       "Exploring Expect: A Tcl-Based Toolkit for Automating Interactive  Pro‐
176       grams" by Don Libes, O'Reilly and Associates, January 1995.
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AUTHOR

179       Don Libes, National Institute of Standards and Technology
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181       expect  and  autoexpect  are  in  the  public domain.  NIST and I would
182       appreciate credit if these programs or parts of them are used.
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187                                 30 June 1995                    AUTOEXPECT(1)
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