Re: GNU Parallel Bug Reports parallel can't ressigned variablen in the same context in same file

[gmail]

On 05/30/2012 11:11 PM, Andreas Bernauer wrote:

On 5/29/12 11:26, gmail wrote:

hello
is it a bug to parallel or parallel can't do like this ?

today , i used  parallel to my shell script ,but read all the
document,no referent  about variable ouside parallel.

bash test code like that:

###################
#!/bin/bash

foo=33

parallel "foo=44;echo $foo;"

above code response 44
####################

For me, your code works as I'd expect it:
- $foo gets expanded to 33 before parallel is even run, because '$foo'
is in double quotes ("), not single quotes (')
- parallel does not run anything but awaits input from the terminal,
printing a message about this circumstance.

#############
$ cat /tmp/par
#!/bin/bash
foo=33
parallel "foo=44;echo $foo;"
$ bash /tmp/par
parallel: Input is read from the terminal. Only experts do this on
purpose. Press CTRL-D to exit.
^D
$ bash /tmp/par
parallel: Input is read from the terminal. Only experts do this on
purpose. Press CTRL-D to exit.
1
^D
bash: 1: command not found
33
#############

Note the output '33' after bash's complain.

If you want to use foo in your parallel script, you must take care that
'$foo' is not expanded in the parallel script, for example by escaping
the '$' sign or putting the command in single quotes. Example for the
former:

#####################
$ cat /tmp/par2
#!/bin/bash
foo=33
parallel "foo=44;echo \$foo;"
$ bash /tmp/par2
parallel: Input is read from the terminal. Only experts do this on
purpose. Press CTRL-D to exit.
1
^D
bash: 1: command not found
44
###################

Note that now the output is '44' after bash's complain.

HTH,

Andreas.

thanks your reply ahead.  Andreas

My aim is that shell variable which in parallel  can modify in the whole shell script context ,

the sample code below like that:
enviroment : centos  5.5 x64 (bash 3.2.25)
##############
#!/bin/bash
domains=('www1'  'www2')
counter=0
parallel -j 2 "if [ -z $counter ];then echo 'var no set ';fi;counter=$((counter + 1));echo $counter {1} " ::: address@hidden

##############
the variable  counter no  to be increased when looping the array domains ,  counter should be 2,but in parallel it print zero( no changed)

 i hope i can describe my quesion  for help above  like that.