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Replace all tabs with spaces in an application
Note that this assumes the application is an SVN checkout and so we have to throw away all the .svn files before making the substitution.

Convert decimal numbers to binary
Convert some decimal numbers to binary numbers. You could also build a general base-converter: $ function convBase { echo "ibase=$1; obase=$2; $3" | bc; } then you could write $ function decToBun { convBase 10 2 $1; }

apt-get upgrade with bandwidth limit
in Debian-based systems apt-get could be limited to the specified bandwidth in kilobytes using the apt configuration options(man 5 apt.conf, man apt-get). I'd quote man 5 apt.conf: "The used bandwidth can be limited with Acquire::http::Dl-Limit which accepts integer values in kilobyte. The default value is 0 which deactivates the limit and tries uses as much as possible of the bandwidth..." "HTTPS URIs. Cache-control, Timeout, AllowRedirect, Dl-Limit and proxy options are the same as for http..."

list block devices
Shows all block devices in a tree with descruptions of what they are.

Use color grep by default
Alias the grep command to show colored results by default.

Check general system error on AIX
Check general system error on AIX

When was your OS installed?
Show time and date when you installed your OS.

copy root to new device
Clone a root partition. The reason for double-mounting the root device is to avoid any filesystem overlay issues. This is particularly important for /dev. Also, note the importance of the trailing slashes on the paths when using rsync (search the man page for "slash" for more details). rsync and bash add several subtle nuances to path handling; using trailing slashes will effectively mean "clone this directory", even when run multiple times. For example: run once to get an initial copy, and then run again in single user mode just before rebooting into the new disk. Using file globs (which miss dot-files) or leaving off the trailing slash with rsync (which will create /mnt/target/root) are traps that are easy to fall into.

Convert a date to timestamp
Simple way to get a timestamp from a date

See a full list of compiler defined symbols
From http://lists.debian.org/debian-devel/2001/01/msg00971.html .


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