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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

make directory with current date

See loaded modules in apache
Easiest way to check which modules are loaded in apache.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

sed edit-in-place using -a option instead of -i option (no tmp file created)
does the -i option open a tmp file? this method does not.

Create a temporary file
To create directory, use: $ tempdir=$(/bin/mktemp -d)

Print a list of all hardlinks in the working directory, recursively
libpurple likes to hardlink files repeatedly. To ignore libpurple, use sed: | sed '/\.\/\.purple/d'

Rename files in batch

print/scan lines starting at record ###
Useful for finding newly added lines to a file, tail + can be used to show only the lines starting at some offset. A syslog scanner would look at the file for the first time, then record the end_of_file record number using wc -l. Later (hours, days), scan only at the lines that were added since the last scan.


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