/bin/rm: Argument list too long.

root@mx /var/virusmails # ls
razor-agent.log
spam-3398a20c9a59797df9b57fbe34feeace-20040519-084342-19051-05.gz
spam-57e230b6d1dca0dadf83d858d0b10788-20040519-084400-19144-03.gz
spam-6f3be6d2304f90e418db23443916101a-20040519-082357-18227-10.gz
virus-20040419-091017-12544-01
virus-20040419-130621-14993-07
virus-20040421-120113-57877-07
virus-20040421-165651-61698-07
virus-20040423-020850-90966-03
virus-20040423-090733-97665-04
virus-20040427-211030-99133-07
virus-20040427-225312-01622-01
virus-20040428-190241-18845-05
virus-20040505-103654-59956-10

root@mx /var/virusmails # rm spam-*
/bin/rm: Argument list too long.
How many files was I dealing with here?
root@mx /var/virusmails # ls -1 | grep virus | wc -l
1667

This is not a limitation of the rm command, but a kernel limitation on the size of the parameters of the command. Since I was performing shell globbing (selecting all the files with extension .wrk), this meant that the size of the command line arguments became bigger with the number of the files involved. For who cares this is defined by:
egrep ARG_MAX /usr/include/linux/limits.h

#define ARG_MAX 131072 /* # bytes of args + environ for exec() */


Solution is to remove file through following find command

root@mx /var/virusmails # find . -name 'spam-*' | xargs rm
it works like a charm.