Add new command to Bash.org

This commit is contained in:
Jeffrey Serio 2024-09-21 00:29:12 -05:00
parent c0c16b9b6e
commit e83d4e01b9

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@ -32,3 +32,15 @@ cat urls.html | grep -Eo "(http|https)://[a-zA-Z0-9./?=_%:-]*"
- ~:~: match colon - ~:~: match colon
- ~-~: match dash - ~-~: match dash
- ~*~: repeat the [...] group any number of times - ~*~: repeat the [...] group any number of times
** Use Awk to print the first line of ~ps aux~ output followed by each grepped line
To find all cron processes with ~ps aux~.
#+BEGIN_SRC bash
ps aux | awk 'NR<2{print $0;next}{print $0 | grep "cron"}' | grep -v "awk"
#+END_SRC
- ~ps aux~ : equivalent to ~ps -aux~. ~-a~ displays info about other users processes besides to current user. ~-u~ displays info associated with keywords ~user~, ~pid~, ~%cpu~, ~%mem~, ~vsz~, ~rss~, ~tt~, ~state~, ~start~, ~time~, and ~command~. ~-x~ includes processes which do not have a controlling terminal. See ~man 1 ps~.
- ~awk 'NR<2{print $0;next}{print $0 | "grep cron"}' | grep -v "awk"~ : For number of input records (~NR~) less than 2, ~print~ the input record (~$0~), go to the next input record and repeat the ~{print $0}~ pattern until the end is reached, then execute the END rule. The End rule in this case is ~{print $0 | "grep cron"}~, it prints the remaining input records after piping them through the ~"grep cron"~ command. This allows printing the first line of the ~ps aux~ output, which consists of the column labels, and filters out everything besides what you want to grep for (e.g. "cron" processes).
- ~grep -v "awk"~ : avoids printing the line containing this command.