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Top Forums UNIX for Dummies Questions & Answers Anyone know?: How the 'for'-loop could stop working in interactive bash shell?! Post 302256669 by alex_5161 on Monday 10th of November 2008 10:41:14 AM
Old 11-10-2008
Thank you, drl, set -x realy interesting thing.

It seems the shell some how do not processing assighment in the (( )).
Also in 'let' and in 'expr' ('ec' is an alianse for echo)
Code:
>ec $i; expr i++; ec $i
+ /usr/bin/echo 2
2
+ expr i++
i++
+ /usr/bin/echo 2
2
>ec $i; expr i++; expr i=1; ec $i
+ /usr/bin/echo 2
2
+ expr i++
i++
+ expr i=1
i=1
+ /usr/bin/echo 2
2
>ec $i; expr i++; let i=1; ec $i
+ /usr/bin/echo 2
2
+ expr i++
i++
+ let i=1
+ /usr/bin/echo 2
2
>ec $i; expr i++; i=1; ec $i
+ /usr/bin/echo 2
2
+ expr i++
i++
+ i=1
+ /usr/bin/echo 1
1
>ec $i; expr i++; i=$((i++)); ec $i
+ /usr/bin/echo 1
1
+ expr i++
i++
+ i=1
+ /usr/bin/echo 1
1
>

 

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echo(1B)					     SunOS/BSD Compatibility Package Commands						  echo(1B)

NAME
echo - echo arguments to standard output SYNOPSIS
/usr/ucb/echo [-n] [argument] DESCRIPTION
echo writes its arguments, separated by BLANKs and terminated by a NEWLINE, to the standard output. echo is useful for producing diagnostics in command files and for sending known data into a pipe, and for displaying the contents of envi- ronment variables. For example, you can use echo to determine how many subdirectories below the root directory (/) is your current directory, as follows: o echo your current-working-directory's full pathname o pipe the output through tr to translate the path's embedded slash-characters into space-characters o pipe that output through wc -w for a count of the names in your path. example% /usr/bin/echo "echo $PWD | tr '/' ' ' | wc -w" See tr(1) and wc(1) for their functionality. The shells csh(1), ksh(1), and sh(1), each have an echo built-in command, which, by default, will have precedence, and will be invoked if the user calls echo without a full pathname. /usr/ucb/echo and csh's echo() have an -n option, but do not understand back-slashed escape characters. sh's echo(), ksh's echo(), and /usr/bin/echo, on the other hand, understand the black-slashed escape characters, and ksh's echo() also understands a as the audible bell character; however, these commands do not have an -n option. OPTIONS
-n Do not add the NEWLINE to the output. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWscpu | +-----------------------------+-----------------------------+ SEE ALSO
csh(1), echo(1), ksh(1), sh(1), tr(1), wc(1), attributes(5) NOTES
The -n option is a transition aid for BSD applications, and may not be supported in future releases. SunOS 5.11 3 Aug 1994 echo(1B)
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