See hidden characters in a string

perl -e '$HOSTNAME = `hostname -s`; print $HOSTNAME;' | od -c

Easily add colours to bash scripts

RED="$(tput setaf 1)"
GREEN="$(tput setaf 2)"
YELLOW="$(tput setaf 3)"
WHITE="$(tput setaf 7)"
RESET=$WHITE

echo "${RED}An error occurred${RESET}"
echo "${YELLOW}Warning: Be careful${RESET}"
echo "${GREEN}Everything is groovy${RESET}"

(source)

Old, naive way:

GREEN="\[\033[32m\]"
YELLOW="\[\033[33m\]"
RESET="\[\033[0m\]"

Find dodgy characters in a file

This will print any characters with values higher than 127, i.e. non-ascii characters that might look like ascii, but really be breaking your processor.

perl -lne'while (my ($c) = $_ =~ m{^(.)}) { print "$c = ".ord($c) if ord($c) > 127; $_ =~ s/^.// }' file_to_check.something


A quick, manual way to confirm some characters really are what you think they are:

cat file_to_check.something | od -bc

Insert non-printable characters in vi

• Ctrl-V, then Ctrl-[X]

Where [X] is A-F

Show/hide invisible/non-printable characters in Outlook (and probably Word)

Control-Shift-8