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Preserve colors when piping tree to less

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" }

Filter IP's in apache access logs based on use
The first sort is necessary for ips in a list to be actually unique.

execute a shell with netcat without -e
Shorter version with proper stderr redirection .

copy paste multiple binary files
Useful when you have multiple files or binary files that you need to transfer to a different host and scp or the like is unavailable. To unpack on the destination host copy paste output using the opposite order: openssl enc -d -base64 | gunzip | tar -x Terminate openssl input using ^d Note: gzip is outside of tar because using -z in tar produces lots of extra padding.

shell function to underline a given string.
underline() will print $1, followed by a series of '=' characters the width of $1. An optional second argument can be used to replace '=' with a given character. This function is useful for breaking lots of data emitted in a for loop into sections which are easier to parse visually. Let's say that 'xxxx' is a very common pattern occurring in a group of CSV files. You could run $ grep xxxx *.csv This would print the name of each csv file before each matching line, but the output would be hard to parse visually. $ for i in *.csv; do printf "\n"; underline $i; grep "xxxx" $i; done Will break the output into sections separated by the name of the file, underlined.

Ping all hosts on 192.168.1.0/24
Will report back IP address's of all hosts that are UP.

Find the package a command belongs to on debian-based distros
Advanced revision to the command 8776 . This revision follows symbolic links. The quotation-marks surrounding $(which $1) allows for graceful handling of errors ( ie. readlink does not complain incase 'which' command generates (null) output)

determine if tcp port is open

Copy a file with progress and save hash to a different file


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