This is a variation on the first style: echo “1 2 3 4″ | gawk ‘BEGIN { OFS=” 🙁 “}; {$1=$1; print $0}’ Results: 1 🙁 2 🙁 3 🙁 4 Explanation: the $1=$1 is to rebuild the record, using the current OFS (you can also see http://www.gnu.org/software/gawk/manual/gawk.html#Changing-Fields) Update: (suggested by @EdMorton and @steve) This … Read more
To print every second line, starting with the first: awk ‘NR%2==1’ file.txt To print every tenth line, starting with the tenth line: awk ‘NR%10==0’ file.txt To use this in a script, add the following to a file called script.awk: BEGIN { print “Processing file” } NR%10==0 END { print “Finished processing” } Then execute: awk … Read more
With GNU awk: echo abbc | awk ‘{ print gensub(/a(b*)c/, “Here are bees: \\1”, “g”, $1);}’ See manual here to see the difference between gsub and gensub gensub() provides an additional feature that is not available in sub() or gsub(): the ability to specify components of a regexp in the replacement text. This is done … Read more
Just use var = var1 var2 and it will automatically concatenate the vars var1 and var2: awk ‘{new_var=$1$2; print new_var}’ file You can put an space in between with: awk ‘{new_var=$1″ “$2; print new_var}’ file Which in fact is the same as using FS, because it defaults to the space: awk ‘{new_var=$1 FS $2; print … Read more
My sed (Mac OS X) didn’t work with +. I tried * instead and I added p tag for printing match: sed -n ‘s/^.*abc\([0-9]*\)xyz.*$/\1/p’ example.txt For matching at least one numeric character without +, I would use: sed -n ‘s/^.*abc\([0-9][0-9]*\)xyz.*$/\1/p’ example.txt
The shebang line has never been specified as part of POSIX, SUS, LSB or any other specification. AFAIK, it hasn’t even been properly documented. There is a rough consensus about what it does: take everything between the ! and the \n and exec it. The assumption is that everything between the ! and the \n … Read more