Commands tagged dangerous (5)

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get total of inodes of root partition

Backup a directory structure
Copies a directory structure from /home/ to /backups/home (notice that the destination does not have a trailing slash)

Use md5sum to check your music and movie files. Also use diff.
This is a beginning script. You can create a file with > filename. You can also use diff to compare output run at different times to verify no change in your files. I apologize in advance if this is too simple. For some it should be a start.

Monitor the queries being run by MySQL
Watch is a very useful command for periodically running another command - in this using mysqladmin to display the processlist. This is useful for monitoring which queries are causing your server to clog up. More info here: http://codeinthehole.com/archives/2-Monitoring-MySQL-processes.html

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

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"

Route outbound SMTP connections through a addtional IP address rather than your primary

Generate a random text color in bash
The expression $(( $RANDOM * 6 / 32767 + 1 )) generates a random number between 1 and 6, which is then inserted into the escape sequence \e[3_m to switch the foreground color of the terminal to either red, green, yellow, blue, purple or cyan. The color can be reset using the escape sequence \e[0m. The full list of colors can be found here: https://wiki.archlinux.org/index.php/Color_Bash_Prompt#List_of_colors_for_prompt_and_Bash

generate a telephone keypad
seems a useless command ...

Sort on multiple dis-contiguous keys/fields (can even specify key number/field from the end)
Notes: 1) -n-1 means sort key is the last field 2) -l is important if each separate record is on a new line (usually so for text files) 3) -j tells msort not to create log file (msort.log) in the working directory 4) may need to install msort package. 5) msort does lot more. Check man msort


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