A purely bash solution, requires two steps to strip prefix & suffix separately (but probably runs faster, because no subprocesses):
#!/bin/bash
orig='from=someuser@somedomain.com, '
one=${orig#*from=}
two=${one%,*}
printf "Result:\n"
printf "$orig\n"
printf "$one\n"
printf "$two\n"
Output:
Result:
from=someuser@somedomain.com,
someuser@somedomain.com,
someuser@somedomain.com
Notes:
${var#*pattern} using # strips from the start of $var up to pattern${var%pattern*} using % strips from end of $var, up to pattern- similar could be accomplished with
${var/pattern/replace} (and leaving replace blank), but it's trickier since full regexp isn't supported (ie, can't use ^ or '$'), so you can't do (for example) /^from=//, but you could do in step one ${var/*from=/} and then in step two, do ${var/,*/} (depending on your data, of course).
- see also: http://www.tldp.org/LDP/abs/html/parameter-substitution.html
