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Display all shell functions set in the current shell environment
Uses the shell builtin `declare` with the '-f' flag to output only functions to grep out only the function names. You can use it as an alias or function like so: alias shfunctions="builtin declare -f | command grep --color=never -E '^[a-zA-Z_]+\ \(\)'" shfunctions () { builtin declare -f | command grep --color=never -E '^[a-zA-Z_]+\ \(\)'; }

monitor a tail -f command with multiple processes
when using named pipes only one reader is given the output by default. Also, most commands piped to by grep use a buffer which save output until tail -f finishes, which is not convenient. Here, using a combination of tee, sub-processes and the --line-buffered switch in grep we can workaround the problem.

Compress blank lines

Get current Xorg resolution via xrandr
Not sure if it works the same on any shell.

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"

get the top 10 longest filenames

MySQL: Slice out a specific table from the output of mysqldump
Only filters the statement related to a specific table ('departments', in the example), from the output of mysqldump

grep for minus (-) sign
Use flag "--" to stop switch parsing

prevent large files from being cached in memory (backups!)
We all know... $ nice -n19 for low CPU priority.   $ ionice -c3 for low I/O priority.   nocache can be useful in related scenarios, when we operate on very large files just a single time, e.g. a backup job. It advises the kernel that no caching is required for the involved files, so our current file cache is not erased, potentially decreasing performance on other, more typical file I/O, e.g. on a desktop.   http://askubuntu.com/questions/122857 https://github.com/Feh/nocache http://packages.debian.org/search?keywords=nocache http://packages.ubuntu.com/search?keywords=nocache   To undo caching of a single file in hindsight, you can do $ cachedel   To check the cache status of a file, do $ cachestats

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.


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