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Top Forums Shell Programming and Scripting Something went wrong in the following loop Post 302179954 by era on Saturday 29th of March 2008 07:42:23 AM
Old 03-29-2008
Superficially, it looks okay. Usually this happens when you have an "else" without a prior "if" but as far as I could quickly see, these are balanced. We could speculate that there is something outside the part you posted (or perhaps invisible control characers we can't see) which are masking out one of the early "if"s. A typical problem is if you have a missing closing quote somewhere; it's okay, in shell syntax, to have multi-line strings, so the string runs on and on and on and a large part of your script ends up missing because it's inside the string when finally another balancing close quote is encountered.

Maybe an example is better to show this.

Code:
if 'true magic is false; then
  echo I snot
  echo foo!'
else
  implode --violent --fireworks
fi

See? So the "then" never happens as far as the shell is concerned, because it's inside a string, and then it acts surprised when it sees an "else" where it expected a "then". The reason is that the opening quote on the first line starts a long string which only ends just before the else.

This should quickly become evident if you run with set -vx but if it's a large script, of course, it all scrolls by very fast. 2>&1 | less is your friend.

Last edited by era; 03-29-2008 at 08:46 AM.. Reason: Note about set -vx
 

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SCRIPT(1)						    BSD General Commands Manual 						 SCRIPT(1)

NAME
script -- make typescript of terminal session SYNOPSIS
script [-akq] [-t time] [file [command ...]] DESCRIPTION
The script utility makes a typescript of everything printed on your terminal. It is useful for students who need a hardcopy record of an interactive session as proof of an assignment, as the typescript file can be printed out later with lpr(1). If the argument file is given, script saves all dialogue in file. If no file name is given, the typescript is saved in the file typescript. If the argument command is given, script will run the specified command with an optional argument vector instead of an interactive shell. The following options are available: -a Append the output to file or typescript, retaining the prior contents. -k Log keys sent to program as well as output. -q Run in quiet mode, omit the start and stop status messages. -t time Specify time interval between flushing script output file. A value of 0 causes script to flush for every character I/O event. The default interval is 30 seconds. The script ends when the forked shell (or command) exits (a control-D to exit the Bourne shell (sh(1)), and exit, logout or control-D (if ignoreeof is not set) for the C-shell, csh(1)). Certain interactive commands, such as vi(1), create garbage in the typescript file. The script utility works best with commands that do not manipulate the screen. The results are meant to emulate a hardcopy terminal, not an addressable one. ENVIRONMENT
The following environment variable is utilized by script: SHELL If the variable SHELL exists, the shell forked by script will be that shell. If SHELL is not set, the Bourne shell is assumed. (Most shells set this variable automatically). SEE ALSO
csh(1) (for the history mechanism). HISTORY
The script command appeared in 3.0BSD. BUGS
The script utility places everything in the log file, including linefeeds and backspaces. This is not what the naive user expects. It is not possible to specify a command without also naming the script file because of argument parsing compatibility issues. When running in -k mode, echo cancelling is far from ideal. The slave terminal mode is checked for ECHO mode to check when to avoid manual echo logging. This does not work when in a raw mode where the program being run is doing manual echo. BSD
January 22, 2004 BSD
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