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View and review the system process tree.
The "pstree" command uses special line-drawing characters. However, when piped into the "less" pager, these are normally disabled.

tree by modify time with newest file at bottom
Go look at sample output first This is kind of like the ls command but displays by modify time with size, date and color. The newest files at the bottom of the screen (reverse using tac)

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" }

Add strikethrough to text

Convert YAML to JSON
* Output is jq compatible * Output is single lines - unix compatible * Multiple files supported

Awk: Perform a rolling average on a column of data
Sometimes jittery data hides trends, performing a rolling average can give a clearer view.

Exclude inserting a table from a sql import
Starting with a large MySQL dump file (*.sql) remove any lines that have inserts for the specified table. Sometimes one or two tables are very large and uneeded, eg. log tables. To exclude multiple tables you can get fancy with sed, or just run the command again on subsequently generated files.

Find writable files
Have a grudge against someone on your network? Do a "find -writable" in their directory and see what you can vandalize! But seriously, this is really useful to check the files in your own home directory to make sure they can't inadvertently be changed by someone else's wayward script.

Remove security limitations from PDF documents using ghostscript
Remove security from PDF document using this very simple command on Linux and OSX. You need ghostscript for this baby to work.

Print all /etc/passwd lines with duplicated uid
Prints all the lines in /etc/passwd belonging to users with a duplicated uid. It also adds the hostname to the beginning of the line. It's been tested in AIX, Solaris and Linux.


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