July
1st,
2019
To format strings in awk use printf
➜ echo '139.162.0.0/19' | awk 'BEGIN{FS="/"}{printf "\"%s\",%s,false\n",$1,$2}'
"139.162.0.0",19,false
To print all but very first column
(venv) ➜ notes git:(master) ✗ history | head -4
1 ag ecr
2 cat .circleci/config.yml
3 cat ./circle_ci_deploy
4 cat ./build_and_push
(venv) ➜ notes git:(master) ✗ history | awk '{$1="";print $0}' | head -4
ag ecr
cat .circleci/config.yml
cat ./circle_ci_deploy
cat ./build_and_push
Print all but 2 first columns
(venv) ➜ notes git:(master) ✗ history | awk '{$1=$2="";print $0}' | head -4
ecr
.circleci/config.yml
./circle_ci_deploy
./build_and_push
A BEGIN rule is executed ONCE only, before the first input record is read. Likewise, an END rule is executed ONCE only, after all the input is read. stackoverflow
$ seq 5 | awk 'BEGIN{print "Hello"}/4/{print}' # Hello printed once
Hello
4
$ seq 5 | awk '{print "Hello"}/4/{print}' # Hello printed for each line of input
Hello
Hello
Hello
Hello
4
Hello
Another example would be like printing headers likegeeks.com
history | awk 'BEGIN {print "These are from history"} {print $1,$2}' | head -5
These are from history
1 ag
2 cat
3 cat
4 cat
Only prints once the count is done for given column values.
➜ notes git:(master) git log --shortstat --since "1 day ago" \
| grep "files changed" \
| awk '{files+=$1; inserted+=$4; deleted+=$6} END {print "files changed", files, "lines inserted:", inserted, "lines deleted:", deleted}'
files changed 26 lines inserted: 185 lines deleted: 19
- To skip blank lines
➜ hdm git:(master) ✗ ls -ltr | awk -F " " '{print $9}' | awk -F "." '{print $1}'
forge-eks-setup
hdm-gap-analysis
hdm-apps
quay-secrets
sumologic
hdm-journal
index
➜ hdm git:(master) ✗ ls -ltr | awk -F " " '{print $9}' | awk -F "." 'NF {print $1}'
forge-eks-setup
hdm-gap-analysis
hdm-apps
quay-secrets
sumologic
hdm-journal
index
- Get all files in the folder and create markdown links
ls -ltr | awk -F " " '{print $9}' | awk -F "." 'NF {print "["$1"]""("$1".md"")"}'
[forge-eks-setup](forge-eks-setup.md)
[hdm-gap-analysis](hdm-gap-analysis.md)
[hdm-apps](hdm-apps.md)
[quay-secrets](quay-secrets.md)
[sumologic](sumologic.md)
[hdm-journal](hdm-journal.md)