6 # $HOME/.flag-cache <- Autogenerated flag (refreshed when hostname changes)
7 # /etc/flag <- Site admin's flag
8 # $HOME/.flag <- Local user's flag
9 # Check them in that order.
11 # Name available algos as algo_something() and left-align for autodetection
12 # Order the algos by priority: the first one that is correct will be used
13 algo_cksum_linux() { printf '%08x\n' $(cksum) | head -n 1; }
14 algo_cksum_freebsd() { printf '%08x\n' $(cksum -o 3) | head -n 1; }
15 algo_crc32() { crc32 /dev/stdin; }
16 algo_crc32sum() { crc32sum; }
17 algo_crc32sum_linux() { crc32sum-linux; }
18 algo_crc32sum_freebsd() { crc32sum-freebsd; }
19 algo_ruby() { ruby -e 'require "zlib"; printf "%08x\n", Zlib.crc32(STDIN.readlines.join)'; }
20 algo_php() { php -r 'printf("%08x\n", crc32(file_get_contents("/dev/stdin")));'; }
21 algo_perl() { perl -e 'use String::CRC32; printf("%08x\n", crc32(*STDIN));'; }
24 sed -e '/^algo_[^(]*()/!d; s/().*$//' "${0}" | while read algo
26 if [ "$(printf "meow" | "${algo}" 2>/dev/null)" = "8a106afe" ]
35 # Hash the passed string into 8 hex characters
36 [ "${crc32_algo}" ] || crc32_algo="$(find_crc32_algo)"
37 if [ -z "${crc32_algo}" ]
39 echo "No crc32 algo found!" >&2
43 echo -n "${*}" | "${crc32_algo}" 2>/dev/null | awk '{print $1}'
49 myhost="$(/bin/hostname -f)"
50 cache="${HOME}/.flag-cache"
53 flag_hex="$(awk '/^'${myhost}'/{print $2}' "${cache}")"
55 if [ -z "${flag_hex}" ]
57 flag_hex="$(hash_string "${myhost}")" && echo -e "${myhost}\t${flag_hex}" >> "${cache}"
62 if [ -f "${HOME}/.flag" ]
64 flag_hex="$(cat "${HOME}/.flag")"
67 if [ -z "${flag_hex}" -a -f "/etc/flag" ]
69 flag_hex="$(cat "/etc/flag")"
72 if [ -z "${flag_hex}" ]
74 flag_hex="$(flagcache)"
77 # Now we definitely have flag_hex
79 eval $(echo -n "${data}" | sed -e 's/^\(.\)\(.*\)$/char="\1" data="\2"/g')
88 echo $(( 0x${1} + 0 ))
94 echo "Usage: flag 'hexcode' [symbol] [shellmode]" >&2
95 echo "Generates an ANSI color flag using the specified hex codes" >&2
96 echo "Uses the optional symbol (or ' ') to draw the flag" >&2
97 echo "shellmode encapsulates all nonprintable codes in \[\] to" >&2
98 echo " give the shell hints on how long the string is, for proper" >&2
99 echo " wrapping of command prompts." >&2
105 [ -n "${shm}" ] && open='\\[' shut='\\]'
106 while [ -n "${data}" ]
109 ord=$(hexdec "${char}")
111 [ "$(( ${ord} & 8 ))" -gt 0 ] && bright="1;7"
112 colour="$(( ${ord} & 7 ))"
113 printf "${open}\033[%s;3%s;4%sm${shut}%s" "${bright}" "${colour}" "${colour}" "${sym:-${char}}"
115 printf "${open}\033[0m${shut}"
119 echo "Usage: $(basename "${0}") [-s #] [-e]" >&2
120 echo "Produces a neat little ansi colour 'flag' based off" >&2
121 echo " a hash of the machine's hostname (or settable via" >&2
122 echo " ~/.flag or /etc/flag) which can uniquely visually" >&2
123 echo " identify a machine, at a glance. Useful for placing" >&2
124 echo " into /etc/issue or your bash prompt, so that you" >&2
125 echo " don't send stupid commands to the wrong machine." >&2
127 echo " -s # Specify which character should be used to" >&2
128 echo " render the flag. If empty, use the hex code." >&2
129 echo " -e Turn on bash encapsulation mode, to provide" >&2
130 echo " hints to Bash on what is or is not printable" >&2
131 echo " so it can wrap your commands appropriately" >&2
132 echo " when used in your prompt" >&2
134 echo "This machine's flag is as such: ($(flag "${flag_hex}"))" >&2
144 -s) shift; symbol="${1}" ;;
145 -e) shellmode="yes" ;;
150 flag "${flag_hex}" "${symbol}" "${shellmode}"