I just started learning expect scripting.I have been trying to extract the following from my output:
core.4046140998.01.10.133211
with an e
Since this is expect, "core" may appear at the beginning of a line, but not at the beginning of the input string. To demonstrate:
$ expect
expect1.1> spawn sh
spawn sh
8043
expect1.2> send "echo core.1234\r"
expect1.3> exp_internal 1
expect1.4> expect -re {^core.*}
Gate keeper glob pattern for '^core.*' is 'core*'. Activating booster.
expect: does "" (spawn_id exp6) match regular expression "^core.*"? Gate "core*"? gate=no
sh-4.3$ echo core.1234
core.1234
sh-4.3$
expect: does "sh-4.3$ echo core.1234\r\ncore.1234\r\nsh-4.3$ " (spawn_id exp6) match regular expression "^core.*"? Gate "core*"? gate=yes re=no
expect: timed out
expect1.5> expect -re {(?n)^core.*}
Gate keeper glob pattern for '(?n)^core.*' is 'core*'. Activating booster.
expect: does "sh-4.3$ echo core.1234\r\ncore.1234\r\nsh-4.3$ " (spawn_id exp6) match regular expression "(?n)^core.*"? Gate "core*"? gate=yes re=yes
expect: set expect_out(0,string) "core.1234\r"
expect: set expect_out(spawn_id) "exp6"
expect: set expect_out(buffer) "sh-4.3$ echo core.1234\r\ncore.1234\r"
expect1.6> puts ">>>$expect_out(0,string)<<<"
<<<core.1234
Things to note:
-re {^core.*}
did not match. We see the "timed out" messagenote what we're attempting to match:
expect: does "sh-4.3$ echo core.1234\r\ncore.1234\r\nsh-4.3$ " (spawn_id exp6) match regular expression "^core.*"? Gate "core*"? gate=yes re=no
# ............^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It starts with the command I sent, so using a "normal" anchor won't work
the next thing I expect is -re {(?n)^core.*}
. This does match.
(?n)
is a little-used Tcl regex instruction that tells the regex engine we want "newline-sensitive" matching. .
will not match a newline and (more relevant here) that ^
can match immediately after a newline within a multi-line string (similarly for $
)puts
command looks odd. That's due to the carriage return at the end of $expect_out(0,string)
. Be aware of that, and use string trim
as requiredThe take-away lessons here are:
You have missed a .
after \.
:
^(core)\..*(\*)$
\.
matches a literal .
and .
matches any single character.
Or you can use the non-greedy version:
^(core)\.[^*]*(\*)$