Commands using cat (514)

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Display the human-readable sizes of all files and folders in the current directory with 3 decimal places
To sort the list by file/directory size, insert `sort -n |` before `awk`.

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" }

Convert tab separate file (TSV) to JSON with jq
With this command you can convert a tab separate file (TSV) into a JSON file with jq. For example, this input.tsv i-0b9adca882e5e6326 172.16.0.188 i-088dd69e5c3624888 172.16.0.102 i-0e70eac180537d4aa 172.16.0.85 will produce the showed output.

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

Insert a line at the top of a text file without sed or awk or bash loops
Just use '-' to use STDIN as an additional input to 'cat'

Trick find -exec option to execute alias
An alias cannot be executed as command in a find -exec line. This form will trick the command line and let you do the job.

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

Check a server is up. If it isn't mail me.
For some reason the 2&>1 does not work for me, but the shorter stdout/stderr redirection >& works perfectly (Ubuntu 10.04).

Matrix Style
Same as the cool matrix style command ( http://www.commandlinefu.com/commands/view/3652/matrix-style ), except replacing the printed character with randomness. The command mentioned is much faster and thus more true to the matrix. However, mine can be optimized, but I wasted ... i mean spent enough time on it already


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