Extract email addresses from a log using grep or sed

Question

Jan 23 00:46:24 portal postfix/smtp[31481]: 1B1653FEA1: to=<[e-mail]>, relay=mta5.am0.yahoodns.net[98.138.112.35]:25, delay=5.4, delays=0.02/3.2/0.97/1.1, dsn=5.0.0, status=bounced (host mta5.am0.yahoodns.net[98.138.112.35] said: 554 delivery error: dd This user doesn't have a yahoo.com account ([e-mail]) [0] - mta1321.mail.ne1.yahoo.com (in reply to end of DATA command))
Jan 23 00:46:24 portal postfix/smtp[31539]: AF40C3FE99: to=<[e-mail]>, relay=mta7.am0.yahoodns.net[98.136.217.202]:25, delay=5.9, delays=0.01/3.1/0.99/1.8, dsn=5.0.0, status=bounced (host mta7.am0.yahoodns.net[98.136.217.202] said: 554 delivery error: dd This user doesn't have a yahoo.com account ([e-mail]) [0] - mta1397.mail.gq1.yahoo.com (in reply to end of DATA command))

On top of maillog, I would like to extract email addresses enclosed between angular brackets < ... >for example. to=<[e-mail]>[e-mail]

I use cut -d' ' -f7to extract letters, but I'm curious if there is a more flexible way.

Answer 1

With GNU grep, just use a regex that contains the look and perspective:

$ grep -Po '(?<=to=<).*(?=>)' file
[e-mail]
[e-mail]

It says:. Hey, extract all the lines preceding to=<and following>

Answer 2

You can use awkas follows:

awk -F'to=<|>,' '{print $2}' the.log

to=< >, .

Answer 3

sed ( GNU BSD/macOS sed - -E):

sed -E 's/.* to=<(.*)>.*/\1/' file

, , ( ) , .

, , , - sed -E 's/.* to=<([^>]*).*/\1/' file

---

, POSIX, - , BRE ( ):

sed 's/.* to=<\(.*\)>.*/\1/' file

---

fedorqui GNU grep:

grep -Po ' to=<\K[^>]*' file

\K, , , , look-behind ((?<=...), - - ( , : . ).

---

.

, , :

• , .

, , , . . script, , 27- iMac 27 2010 , 250 000 , , 10 .

Mawk                            0.364s
GNU grep, \K, non-backtracking  0.392s
GNU awk                         0.830s
GNU grep, \K                    0.937s
GNU grep, (?>=...)              1.639s
BSD grep + cut                  2.733s
GNU grep + cut                  3.697s
BSD awk                         3.785s
BSD sed, non-backtracking       7.825s
BSD sed                         8.414s
GNU sed                         16.738s
GNU sed, non-backtracking       17.387s

:

• .
• grep , cut
• , , .
• GNU sed , GNU awk BSD awk. , () GNU sed.

---

script, ; , g -prefixed - GNU, macOS Homebrew; , mawk Homebrew.

, "non-backtracking" .

#!/usr/bin/env bash

# Define the test commands.
test01=( 'BSD sed'                        sed -E 's/.*to=<(.*)>.*/\1/' )
test02=( 'BSD sed, non-backtracking'      sed -E 's/.*to=<([^>]*).*/\1/' )
# ---
test03=( 'GNU sed'                        gsed -E 's/.*to=<(.*)>.*/\1/' )
test04=( 'GNU sed, non-backtracking'      gsed -E 's/.*to=<([^>]*).*/\1/' )
# ---
test05=( 'BSD awk'                        awk  -F' to=<|>,' '{print $2}' )
test06=( 'GNU awk'                        gawk -F' to=<|>,' '{print $2}' )
test07=( 'Mawk'                           mawk -F' to=<|>,' '{print $2}' )
#--
test08=( 'GNU grep, (?>=...)'             ggrep -Po '(?<= to=<).*(?=>)' )
test09=( 'GNU grep, \K'                   ggrep -Po ' to=<\K.*(?=>)' )
test10=( 'GNU grep, \K, non-backtracking' ggrep -Po ' to=<\K[^>]*' )
# --
test11=( 'BSD grep + cut'                 "{ grep -o  ' to=<[^>]*' | cut  -d'<' -f2; }" )
test12=( 'GNU grep + cut'                 "{ ggrep -o ' to=<[^>]*' | gcut -d'<' -f2; }" )

# Determine input and output files.
inFile='file'
# NOTE: Do NOT use /dev/null, because GNU grep apparently takes a shortcut
#       when it detects stdout going nowhere, which distorts the timings.
#       Use dev/tty if you want to see stdout in the terminal (will print
#       as a single block across all tests before the results are reported).
outFile="/tmp/out.$$"
# outFile='/dev/tty'

# Make `time` only report the overall elapsed time.
TIMEFORMAT='%6R'

# How many runs per test whose timings to average.
runs=10

# Read the input file up to even the playing field, so that the first command
# doesn't take the hit of being the first to load the file from disk.
echo "Warming up the cache..."
cat "$inFile" >/dev/null

# Run the tests.
echo "Running $(awk '{print NF}' <<<"${!test*}") test(s), averaging the timings of $runs run(s) each; this may take a while..."
{
    for n in ${!test*}; do    
        arrRef="$n[@]"
        test=( "${!arrRef}" )
        # Print test description.
        printf '%s\t' "${test[0]}"
        # Execute test command.
        if (( ${#test[@]} == 2 )); then # single-token command? assume `eval` must be used.
          time for (( n = 0; n < runs; n++ )); do eval "${test[@]: 1}" < "$inFile" >"$outFile"; done
        else # multiple command tokens? assume that they form a simple command that can be invoked directly.
          time for (( n = 0; n < runs; n++ )); do "${test[@]: 1}" "$inFile" >"$outFile"; done
        fi
    done
} 2>&1 | 
  sort -t$'\t' -k2,2n | 
    awk -v runs="$runs" '
      BEGIN{FS=OFS="\t"} { avg = sprintf("%.3f", $2/runs); print $1, avg "s" }
    ' | column -s$'\t' -t

Answer 4

awk -F'[<>]' '{print $2}' file

[e-mail]
[e-mail]