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Compares two versions with dpkg. It is not always obvious what version dpkg/apt will consider to be more recent. Operators include the following :
* These treat an empty version as earlier than any version: lt le eq ne ge gt.
* These treat an empty version as later than any version: lt-nl le-nl ge-nl gt-nl.
* These are provided only for compatibility with control file syntax: < > >.
This command doesn't output anything. It only returns with status 0 or 1, hence the echo "y" || echo "n" to get an output.
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"
}
This will start a netcat process listening on port 666. If you are able connect to your your server, netcat will receive the data being sent and spit it out to the screen (it may look like random garbage, so you might want to redirect it to a file).
Installing most OSX apps is just a matter of dropping it in /Applications, either GUI-wise or with cp -r. However, many packages are distributed in "mpkg" format, and those have to be installed with an installer. If you don't want to go to the trouble of firing up VNC to install an mpkg, you can use the "installer" command.
This will install an application from a .mpkg it to /Applications system-wide. To install a program for just one user, replace "-target /" with "-target username".
Postgresql specific SQL
- to show count of ALL tables including relation-size (pg_relation_size = used space on filesystem)
- might need a VACUUM ANALYZE before showing all counts correctly !
Query the Socrata Open Data API being used by the White House to find any employee's salary using curl, grep and awk.
Change the value of the search parameter (example uses Axelrod) to the name of any White House staffer to see their annual salary.
This is the one-line version of this htmldoc + markdown combo to convert markdown formatted text to PDF files to distribute to your non-savvy project managers.
http://scottnesbitt.net/ubuntublog/?p=114
wget http://nginx.org/download/nginx-1.15.3.tar.gz && tar -xzf 1.15.3.tar.gz && cd nginx-1.15.3
works as well as echo $0, but also prints process id, which pts you're using. echo $SHELL doesn't always get updated when changing shells, so this is a better solution than that. Just one more variation on a theme.
