# It is often useful to pipe the results of a
# MySql query. The below will execute
# an SQL select statement and pipe result to a textfile
mysql database_name -e "sql statement" > sql.txt

# startx with an error log
startx 2>&1 | tee startx.log

# to check the settings being used for your Xserver
# (like xinerama), use "whereis" to locate the startx script:
whereis startx

# then edit that shell script to add server arguments, like:
startx -- +xinerama
# to add Xinerama support, although this can be in the
# config file found in /etc/X11/XF86Config-4.

# to find out what package something belongs to:
rpm -qf /path/to/mysterious_file

# To modify font sizes, so that 12 points looks like
# you expect, you can specify the dpi for the Xserver:
startx -- -dpi 100

# to find what the Xserver currently thinks your dpi is:
xdpyinfo | grep resolution

# to list all fonts:
xlsfonts

# to fax under linux, assuming you have all the
# standard packages for this installed, and have
# printed your document to a postscript file:
fax send -v 123-4567 file.ps

# to make a pdf file from an HTML page, first view the HTML
# in a good browser and print to file(.ps). Then use:
ps2pdf file.ps file.pdf

# directory usage, list the size of directories
du -ch

# amount of swap space used
free

# convert a man page to a textfile
man command | col -b > command.txt

# change the prompt to the current directory and current time:
PS1="[\W \@]"

# tell me the date and time
date

# tell met the date as YYYY-MM-DD
date +%Y-%m-%d

# If I can't remember a command, you can search
# for all commands related to a term
apropos term

# when copying directories, hidden files are skipped.
# They can be copied by stipulating "cp .*", but then
# hidden directories aren't copied recursively. This is an
# issue when I backup my email folders (Kmail), because
# hidden files and directories are used. But there is a
# command to copy directories recursively, including
# hidden files and directories:
rcp -r original new

# Perl can be used to perform a regular expression substitution
# on a series of text files, making backups, using a single command:
perl -pi.bak -e 's/foo/bar/' filelist
# Note: use with caution. Test your regular expression before applying it
# to a large group of files. In the example above, the backup files will
# have the extension ".bak".

# Make a man page from a perldoc:
pod2man Photos.pm > /usr/share/man/man3/Photos.3pm
# after that, "man Photos" will display the Photos module documentation
# in manpage format.

# make an Xauthority file for user Chris
mkxauth -u Chris -c

# find files larger than 1 Megabyte modified less than 250 minutes ago
find / -size +1000k -mmin -250

# to convert a postscript file (.ps) to .jpg, thumbnail size, with ghostscript:
gs -sDEVICE=jpeg -sOutputFile=file.jpg -r20 file.ps

# if booting from a boot disk, and it's necessary for some reason
# to boot into a shell with only the "/" partition mounted (e.g. other
# partitions have errors), enter the below at the "boot>" prompt:
linux init=/bin/sh

# RedHat installations use "cups" for printing
# instead of lpd. The below command will print
# multiple copies of "class3.ps" collated (in this case, 14 copies)
lpr.cups -#14 -o Collate=True class3.ps

# to do a screen capture of a single window, saved as "file.jpg":
import file.jpg

# to make a tar file of all html files in /www
tar -czf pt.tar.gz /www*

# to list files in a gzipped tar archive:
tar -ztf pt.tar.gz

# to see the cookie for a website (not limited to Linux),
# type the below in a web browser's address window and hit enter
javascript:alert(document.cookie)