Description of problem:
When i type C-r and input some characters of the command which i want to complete(nohup), i receive an error from bash:
[root@rhel7 ~]# -bash: ((: -1 ==  : syntax error: operand expected (error token is "==  ")
-bash: ((: -1 >  : syntax error: operand expected (error token is ">  ")

set -x and find the following lines:
.....
complete -F _filedir_xspec dvitype
complete -F _filedir_xspec dviselect
complete -F _filedir_xspec xdvi
complete -F _longopt uniq
complete -F _command tsocks
complete -F _service /etc/rc.d/init.d/network
complete -a unalias'
+ func=_pminfo_complete
+ [[ 2 -ge 2 ]]
+ _pminfo_complete cat ''
+ local cur=anaconda-ks.cfg
+ local opt_regex= curpos_expand=
+ COMPREPLY=()
+ case ${COMP_WORDS[0]} in
+ ((  -1 ==   ))
-bash: ((: -1 ==  : syntax error: operand expected (error token is "==  ")
+ ((  -1 >   ))
-bash: ((: -1 >  : syntax error: operand expected (error token is ">  ")
+ local opt
+ [[ complete -o default -F _pminfo_complete pmstore
complete -o filenames -F _cr_createrepo createrepo
complete -F _minimal 
complete -F _filedir_xspec oodraw
complete -F _filedir_xspec elinks
complete -F _filedir_xspec freeamp
complete -F _longopt split 
.......

The error is caused by a NULL string '${COMP_WORDS[0]}'. I don't know why this string is NULL, when i remove package pcp-3.9.10-4.el7, and redo the test, this time no errors output.

I don't know if it is caused by bash-completion-2.1-6.el7.noarch or pcp-3.9.10-4.el7. File this bug against bash-completion for first review.


Version-Release number of selected component (if applicable):
bash-completion-2.1-6.el7.noarch
pcp-3.9.10-4.el7
Host: RHEL-7.1-20141006.1


How reproducible:
100%


Steps to Reproduce:
1. #nohup cat anyfile.txt &
2. Press C-r and input first two haracters of 'nohup'
#
(reverse-i-search)`no': nohup cat anaconda-ks.cfg &

And then press Tab key.
root@rhel7 ~]# -bash: ((: -1 ==  : syntax error: operand expected (error token is "==  ")
-bash: ((: -1 >  : syntax error: operand expected (error token is ">  ")


Actual results:
Bash output error messages


Expected results:
Complete command 'nohup cat anyfile.txt &' successfully.


Additional info:
verbose info when do these operations.