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Print diagram of user/groups
Parses /etc/group to "dot" format and pases it to "display" (imagemagick) to show a usefull diagram of users and groups (don't show empty groups).

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Clean swap area after using a memory hogging application
When you run a memory intensive application (VirtualBox, large java application, etc) swap area is used as soon as memory becomes insufficient. After you close the program, the data in swap is not put back on memory and that decreases the responsiveness. Swapoff disables the swap area and forces system to put swap data be placed in memory. Since running without a swap area might be detrimental, swapon should be used to activate swap again. Both swapoff and swapon require root privileges.

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" }

decoding Active Directory date format
When Ldapsearch queries an Active directory server, all the dates are shown using a timestamp of 18 digits. This perl regexp decodes them in a more human friendly notation. 11644473600 corresponds to some microsoft epoch.

Re-emerge all ebuilds with missing files (Gentoo Linux)
Revised approach to and3k's version, using pipes and read rather than command substitution. This does not require fiddling with IFS when paths have whitespace, and does not risk hitting command-line size limits. It's less verbose on the missing files, but it stops iterating at the first file that's missing, so it should be definitely faster. I expanded all the qlist options to be more self-describing.

Zip a directory on Mac OS X and ignore .DS_Store (metadata) directory
If you want to generate a cross-platform compatible zip file and ignore the Finder's hidden metadata directory

Rename files in batch

Pimp your less
# s = combine multiple lines of whitespace into 1 # x4 = set the tabstop to 4 instead of 8 # F = Exit if the output fits on 1 screen. This is similar to git diff # R = Raw control chars. This allows you to pipe colordiff straight to less. ie: alias sdi="svn diff | colordiff | less" # S = Chop off long lines # X = Dont send termcap init and deinit scrings to the terminal

tar exclude files or directories
If you want to exclude only one file or directory you should use as --exclude=file_or_directory


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