Dev Blog
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awk Cheatsheet
| Command | Description |
|---|---|
echo -e "a b c\nd e f" | awk '{ print }' |
Print each row |
echo -e "a b c\nd e f" | awk '{ print $0 }' |
Print each row |
echo -e "a b c\nd e f" | awk '{ print $1, $2, $3 }' |
Print each element explicitly for each row |
echo -e "a\tb\tc\nd\te\tf" | awk -F '\t' '{ print $1, $2, $3 }' |
Print each element explicitly, using tab as a field separator |
echo -e "a b c\nd e f" | awk '{ print $(NF-2), $(NF-1), $NF }' |
Print the last three elements in the row |
echo -e "a b c\nd e f" | awk '{ print NR, NF, $0 }' |
Print row number, number of columns and the row |
echo -e "a b c\nd e f" | awk '/ e /{ print NR, $0 }' |
Match regex and then print the row number and the last three fields |
echo -e "a b c\nd e f" | awk '$2 == "e" { print NR, $0 }' |
Test to see if the second field is b and print the row number and row |
echo -e "a b c\nd e f" | awk '$2~/e/{ print $0 }' |
Test if the second field matches regex and print row |
echo -e "a b c\nd e f" | awk '{ printf "ok %s\n", $1 }' |
Use printf to do extra formatting |
echo -e "1 2 3\n4 5 6" | awk 'BEGIN { print "begin" } { tot = tot + $2 } END { print "end:", tot, tot/NR }' |
Calculate the running total and print out the sum and average of the second field |
ls -la | awk '{ print $1, $2, $3, $4 }' |
Print out first four columns of ls -la with duplicate separator tokens consolidated into one |
echo -e "a\tb\tc\nd\te\tf" | awk 'BEGIN { FS = "\t" } { print NF, $0 }' |
Change field separator (FS) to tab and print each row and their field count |
echo -e "a 1\nb 3\nc 7\na 3" | awk '{ print $1,$2; tot[$1]=tot[$1]+$2; count[$1]=count[$1]+1 } END { for (i in count) { print i, tot[i], count[i] } }' |
Arrays |
echo -e "a 1\nb 3\nc 7\na 3" | awk '{ print $1,$2; tot[$1]=tot[$1]+$2; count[$1]=count[$1]+1 } END { for (i in count) { if (count[i] > 1) print ">1", i, tot[i], count[i] ; else if (count[i] < 2) print "<2", i, tot[i], count[i] } }' |
Control flow |