Combine multiple sed commands [duplicate]

Answer 1

Use the -e option. Look it up in man sed

So in your case you could do:

cat tmp.txt | grep '[0-9]*.[0-9]' \
| sed -e 's/[\t ]//g' \
-e "s///g" \
-e "s/kB\/s\((.*)\)//g" \
-e "s/<\/td>//g" > traffic.txt

You can also write it in another way as:

grep ".*" tmp.txt | sed 's/\([0-9.]\+\).*/\1/g'

The \+ matches one or more instances, but it does not work on non-GNU versions of sed. (Mac has BSD, for example)

With help from @tripleee's comment below, this is the most refined version I could get which will work on non-GNU versions of sed as well:

sed -n 's/\([0-9]*.[0-9]*\).*/\1/p' tmp.txt

As a side note, you could also simply pipe the outputs through each sed instead of saving each output, which is what I see people generally do for ad-hoc tasks:

  cat tmp.txt | grep '[0-9]*.[0-9]' \
    | sed -e 's/[\t ]//g' \
    | sed "s///g" \
    | sed "s/kB\/s\((.*)\)//g" \
    | sed "s/<\/td>//g" > traffic.txt

The -e option is more efficient, but the piping option is more convenient I guess.