Bash patterns I use weekly(will-keleher.com)

    grep -l -r pattern /path/to/files | while read x; do echo $x; done

    function my_func() {
        for arg; do
            echo $arg
        done
    }

   preexec ()
   {
       # shellcheck disable=2034
       _CMD_START="$(date +%s)"
   }

   trap 'preexec; trap - DEBUG' DEBUG

   PROMPT_COMMAND="_CMD_STOP=\$(date +%s)
       let _CMD_ELAPSED=_CMD_STOP-_CMD_START

       if [ \$_CMD_ELAPSED -gt 5 ]; then
           _TIME_STR=\" (\${_CMD_ELAPSED}s)\"
       else
           _TIME_STR=''
       fi; "

    PS1="\n\u@\h \w\$_TIME_STR\n\\$ "

    PROMPT_COMMAND+="trap 'preexec; trap - DEBUG' DEBUG"

    some_command &
    some_other_command &
    wait

  > 1. Find and replace a pattern in a codebase with capture groups
  > git grep -l pattern | xargs gsed -ri 's|pat(tern)|\1s are birds|g'

    > SECONDS
    bash: SECONDS: command not found
    > SECONDS=0; sleep 5; echo $SECONDS;
    5
    > echo "Your command completed after $SECONDS seconds";
    Your command completed after 41 seconds
    > echo "Your command completed after $SECONDS seconds";
    Your command completed after 51 seconds
    > echo "Your command completed after $SECONDS seconds";
    Your command completed after 53 seconds

       #!/bin/sh
       (IFS=/;while read w x y z;do
       case $w in http:|https:);;*)exit;esac;
       case $x in "");;*)exit;esac;
       echo $y > .host
       printf '%s\r\n' "GET /$z HTTP/1.1";
       printf '%s\r\n' "Host: $y";
       # add more headers here if desired;
       printf 'Connection: keep-alive\r\n\r\n';done|sed 'N;$!P;$!D;$d';
       printf 'Connection: close\r\n\r\n';
       ) >.http
       read x < .host;
       # SNI;
       #openssl s_client -connect $x:443 -ign_eof -servername $x < .http;
       # no SNI;
       openssl s_client -connect $x:443 -ign_eof -noservername < .http;
       exec rm .host .http;

   for route in foo bar baz do
   curl localhost:8080/$route
   done

  stuff="foo bar baz"
  for route in $stuff; do
  echo curl localhost:8080/$route
  done

  all: cmd1 cmd2
  
  cmd1:
      sleep 5
  
  cmd2:
      sleep 10

  make -j[n]

  cat file
  cat file | grep something

    for thing in $(cat file_with_one_thing_per_line) ; do ...