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Create a 5 MB blank file via a seek hole
Similar to the original, but is much faster since it only needs to write the last byte as zero. A diff on testfile and testfile.seek will return that they are the same.

Remove all hidden files in a directory
Remove all hidden files in a directory excluding current dir . and parent dir .. with .??* that means files with at least two characters.

create a new script, automatically populating the shebang line, editing the script, and making it executable.
The first argument is the interpreter for your script, the second argument is the name of the script to create.

Delete newline

Create a self-signed certificate for Apache Tomcat
Must be run as root. The 'tomcat' user must have access to the .keystore file. The key and keystore passwords must be the same. The password must be entered into the server.xml config file for Tomcat.

kill all foo process
Kill all processes with foo in them. Similar to pkill but more complete and also works when there is no pkill command. Works on almost every Linux/Unix platform I have tried.

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"

output absolute path of the present working directory
I've seen a lot of overly complicated attempts at figuring out "where am I?" I think this is a part of the problem: type -a pwd force the use of the binary version of `pwd` instead of the built-in with "/bin/pwd -P" -P option provides an absolute path to the present working directory for the overly cautious type: $(which pwd) -P

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" }

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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