How to count occurrences of text in a file?

You can use cut and uniq tools:

cut -d ' ' -f1 test.txt  | uniq -c
      5 5.135.134.16
      9 13.57.220.172
      1 13.57.233.99
      2 18.206.226.75
      3 18.213.10.181

Explanation :

• cut -d ' ' -f1 : extract first field (ip address)
• uniq -c : report repeated lines and display the number of occurences

If you don't specifically require the given output format, then I would recommend the already posted cut + uniq based answer

If you really need the given output format, a single-pass way to do it in Awk would be

awk '{c[$1]++} END{for(i in c) print i, "count: " c[i]}' log

This is somewhat non-ideal when the input is already sorted since it unnecessarily stores all the IPs into memory - a better, though more complicated, way to do it in the pre-sorted case (more directly equivalent to uniq -c) would be:

awk '
  NR==1 {last=$1} 
  $1 != last {print last, "count: " c[last]; last = $1} 
  {c[$1]++} 
  END {print last, "count: " c[last]}
'

Ex.

$ awk 'NR==1 {last=$1} $1 != last {print last, "count: " c[last]; last = $1} {c[$1]++} END{print last, "count: " c[last]}' log
5.135.134.16 count: 5
13.57.220.172 count: 9
13.57.233.99 count: 1
18.206.226.75 count: 2
18.213.10.181 count: 3

You can use grep and uniq for the list of addresses, loop over them and grep again for the count:

for i in $(<log grep -o '^[^ ]*' | uniq); do
  printf '%s count %d\n' "$i" $(<log grep -c "$i")
done

grep -o '^[^ ]*' outputs every character from the beginning (^) until the first space of each line, uniq removes repeated lines, thus leaving you with a list of IP addresses. Thanks to command substitution, the for loop loops over this list printing the currently processed IP followed by “ count ” and the count. The latter is computed by grep -c, which counts the number of lines with at least one match.

Example run

$ for i in $(<log grep -o '^[^ ]*'|uniq);do printf '%s count %d\n' "$i" $(<log grep -c "$i");done
5.135.134.16 count 5
13.57.220.172 count 9
13.57.233.99 count 1
18.206.226.75 count 2
18.213.10.181 count 3