CODEWITHSUNDEEP
regexunixsed
matanm
matanm

Reputation: 317

Work only with lines that have 4 words in SED

How to work with lines that have only 4 words in them with SED?

That’s what I managed to do, but it’s not working:

sed -e '/[ ]*[^ ]+[ ]*[^ ]+[ ]*[^ ]+[ ]*[^ ]+[ ]*/!d' -e 'other commands...' fileName

Upvotes: 0

Views: 77

Answers (2)

Cole Tierney
Cole Tierney

Reputation: 10324

This should be portable:

sed -n '
/^[[:blank:]]*\([[:alpha:]]\{1,\}[[:blank:]]\{1,\}\)\{3\}[[:alpha:]]\{1,\}[[:blank:]]*$/ {

    # capture the 1st word of every 4 word line and print it 3 times
    s/^[[:blank:]]*\([[:alpha:]]\{1,\}\).*/\1 \1 \1/
    p

}
' > temp-file

Upvotes: 1

sjsam
sjsam

Reputation: 21965

AWK may be the easier tool for your task. Just check the number of fields in a line is equal to four using the awk built-in variable NF.

awk 'NF==4' filename

would be a good starting point. if you wish to write the changes to file, you can use the inplace edit option of the GNU AWK like below

gawk -i inplace 'NF==4' filename

Upvotes: 0

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