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Filter the output of a file continously using tail and grep
The OPs solution will work, however on some systems (bsd), grep will not filter the data, unless the --line-buffered option is enabled.

download 10 random wallpapers from google
you may want &hl=en for &hl=es for the language you may want imgsz=xxlarge for imgsz=large or whatever filter you may want q=apples or whatever

ls not pattern
Negative shell globs already come with bash. Make sure to turn on extended pattern matching with 'shopt -e extglob'.

list block devices
Shows all block devices in a tree with descruptions of what they are.

Run a command if file/directory changes
Example: $ runonchange /etc/nginx nginx -t Ignores vim temp files. Depends on 'inotify-tools' for monitoring of file changes. Alternative to tools like 'entr', 'watchr'.

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

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" }

View any already in progress copy command in detail
If you spot a dubious looking cp command running you can use this command to view what is being copied and to where. 1234 is the PID of the cp command being passed to the lsof utility. 3r.*REG will display the file/directory that is being read/copied. 4w.*REG will display the destination it is being written to.

escape any command aliases
e.g. if rm is aliased for 'rm -i', you can escape the alias by prepending a backslash: rm [file] # WILL prompt for confirmation per the alias \rm [file] # will NOT prompt for confirmation per the default behavior of the command

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials


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