Shell Programming and Scripting

Hello All,

Does the sed "s/// command" have an equivalent to Perl's vertical pipe character "|", meaning 'OR'...


i.e. To say replace "a" or "b" with "m": (the pipe has a different function in sed... Does it have an 'OR' character?)

Code:

sed 's/(a|b)/m/g'

# This would work in perl (it would replace "a" -OR- "b" with "m")
perl -pe 's/(a|b)/m/g'

I read through the sed man pages and Googled ALL day long and couln't find anything remotley related to an 'OR' character...
Any help would be much appreciated...!


Thanks in Advance,
Matt

( | ) are taken literally unless you escape them. 's/\(a\|b\)/m/g'

According to the POSIX standard, the sed utility uses Basic Regular Expressions (BREs). BREs don't have an the "|" operator. Some, but not all, versions of sed have a -r (or --regexp-extended) option (as an extension to the standard) that causes sed to use Extended Regular Expressions (EREs) instead of BREs. Some other versions of sed have a -E option that serves the same purpose.

EREs do have the "|" operator and would work as you expect in your perl script. The awk utility also uses EREs when selecting lines to process as well as in the sub() and gsub() string functions.

Hope this helps.

Hey Corona688, thanks for your reply.
I tried escaping the "|" but it didn't seem to change anything... Thanks though!


Hey Don Cragun, thanks for the reply...

I used the "-r" and it seems to be working perfectly.
Here's my command:

Code:

### In a bash script while reading a file...
while read line
 do

    # Matches the BOLD, UNDERLINE, and OFF Character Sequences --> (i.e. "^[[1m", "^[[4m", "^[[0m")
    echo "$line" | sed -r 's/\^\[\[(0|1|4)m//g'

    # This REGEX also works... It uses a range instead of "0|1|4"
    echo "$line" | sed -r 's/\^\[\[([0-9])m//g'

done < $myFile

Thanks for your suggestions!

Thanks Again,
Matt

---------- Post updated at 10:22 AM ---------- Previous update was at 10:05 AM ----------

This one also seems to work... And it's without the '-r' (it's an OLDER version of sed that doesn't have the "-r" option).

Code:

        # Basically the same thing as the one above except the range is NOT enclosed in parenthesis...
        echo "$line" | sed 's/\^\[\[[0-9]m//g'

Thanks,
Matt