Commands using cat (514)

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calculate the total size of files in specified directory (in Megabytes)

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"

Speed up builds and scripts, remove duplicate entries in $PATH. Users scripts are oftern bad: PATH=/apath:$PATH type of thing cause diplicate.
Thanks to the authors of: $ awk '!x[$0]++' and the author of: $ joinargs() { (local IFS="$1"; shift && echo "$*") } and others, we can have a fast Linux or android. IMPORTANT if you find a priority order problem in PATH you can push a path directory to the front without duplication as follows: $ PATH=/bin:$PATH then ... Check duplication with: $ echo $PATH|tr : '\n'|sort|uniq -d Finally do a very neat line by line list of $PATH: $ echo "${PATH//:/$'\n'} The speed up is very noticeable for android, and builds on Linux Ubantu are much faster with make and scripts. I will update the command on request. Timothy from SONY

Grab IP address on machine with multiple interfaces
Instead of hard-coding in a check to scrape info from ifconfig based on a specific interface, do it in a more portable way. This works really well if you switch between wired, wireless, bluetooth or even VPN connections. You can get your current IP in a script (since it'll be something like tun0 instead of eth0 or wlan1). This uses a well known public ip address 8.8.8.8, but it doesn't actually connect to it, it just shows you the route it would take.

Check hashes of files installed by Debian packages, reporting only errors.

Backup sda5 partition to ftp ( using pipes and gziped backup )

Advanced python tracing
Trace python statement execution and syscalls invoked during that simultaneously

See system users

quit gvim remotely

floating point operations in shell scripts
Calculator for shell. Similar performance and basic usage as 'bc', but with more advanced features. Not installed on most systems by default.


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