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Resize photos without changing exif
To resize photos without changing exif datas, pretty cool for gps tagging. (Require ImageMagick)

generate a random 10 character password
Generate a table of random 10 character passwords

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"

run command on a group of nodes

Get the ip registered to a domain on OpenWRT
I use this in a script on my openwrt router to check if my DynDNS needs to be updated, saves your account from being banned for blank updates.

show the working directories of running processes
this shows the CWD of every running `java' command. YMMV but we often switch to a working directory for each service to start and run from there -- therefore this quicly shows what is running by a more meaningful name than command alone (the -bw prevents using blocking system calls which speeds this up quite a bit in the presence of remote mounted filesystems)

Huh? Where did all my precious space go ?
Sort ls output of all files in current directory in ascending order Just the 20 biggest ones: $ ls -la | sort -k 5bn | tail -n 20 A variant for the current directory tree with subdirectories and pretty columns is: $ find . -type f -print0 | xargs -0 ls -la | sort -k 5bn | column -t And finding the subdirectories consuming the most space with displayed block size 1k: $ du -sk ./* | sort -k 1bn | column -t

SAR - List the average memory usage for all days recorded under '/var/log/sa/*' using sar -r.

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" }

Grep for regular expression globally, list files and positions.
Grep for expression globally, list files and positions. "Hirn" is a nice german crib meaning "Brain". :-) Afterwards you can edit the line you want with "vi ./p_common/common_main.pbt +1550"


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