8.3. Construction

8.3.1. Write a "more" script

Create the following script with a text editor and save it as ~/staging/bin/more.sh

#!/bin/sh # # more.sh - emulates the basic functions of the "more" binary without # requiring ncurses or termcap libraries. # # Assume input is coming from STDIN unless a valid file is given as # a command-line argument. if [ -f $1 ]; then INPUT="$1" else INPUT="/dev/stdin" fi # # Set IFS to newline only. See BASH(1) manpage for details on IFS. IFS=$'\n' # # If terminal dimensions are not already set as shell variables, take # a guess of 80x25. if [ "$COLUMNS" = "" ]; then let COLUMNS=80; fi if [ "$LINES" = "" ]; then let LINES=25; fi # # Initialize line counter variable let LINE_COUNTER=$LINES # # Read the input file one line at a time and display on STDOUT until # the page fills up. Display "Press <Enter>" message on STDERR and wait # for keypress from STDERR. Continue until the end of the input file. # Any input line greater than $COLUMNS characters in length is wrapped # and counts as multiple lines. # while read -n $COLUMNS LINE_BUFFER; do echo "$LINE_BUFFER" let LINE_COUNTER=$LINE_COUNTER-1 if [ $LINE_COUNTER -le 1 ]; then echo "Press <ENTER> for next page or <CTRL>+C to quit.">/dev/stderr read</dev/stderr let LINE_COUNTER=$LINES fi done<$INPUT # # end of more.sh

Create a symbolic link for more

bash# ln -s more.sh ~/staging/bin/more

8.3.2. Create additional device files

bash# ln -s /proc/self/fd ~/staging/dev/fd bash# ln -s fd/0 ~/staging/dev/stdin bash# ln -s fd/1 ~/staging/dev/stdout bash# ln -s fd/2 ~/staging/dev/stderr bash# mknod -m644 ~/staging/dev/zero c 1 5

8.3.3. Install ps

Get the latest procps source package from http://procps.sourceforge.net/

bash# cd /usr/src/procps-3.2.3 bash# make SHARED=0 CC="gcc -mcpu=i386" bash# cd ps bash# cp ps ~/staging/bin

8.3.4. Install sed

Download GNU's sed from ftp://ftp.gnu.org/gnu/sed/

bash# cd /usr/src/sed-4.1.2 bash# export CC="gcc -mcpu=i386" bash# ./configure --host=i386-pc-linux-gnu bash# make bash# cd sed bash# cp sed ~/staging/bin

8.3.5. Install ed

The ed package also comes from GNU at ftp://ftp.gnu.org/gnu/ed/

bash# cd /usr/src/ed-0.2 bash# ./configure --host=i386-pc-linux-gnu bash# make bash# cp ed ~/staging/bin

8.3.6. Strip binaries to save space

bash# strip ~/staging/bin/*

8.3.7. Ensure proper permissions

bash# chown 0:0 ~/staging/bin/* bash# chmod -R 755 ~/staging/bin bash# chmod 4750 ~/staging/bin/su

8.3.8. Create the root disk image

bash# cd / bash# dd if=/dev/zero of=/dev/ram7 bs=1k count=4096 bash# mke2fs -m0 /dev/ram7 4096 bash# mount /dev/ram7 /mnt bash# cp -dpR ~/staging/* /mnt bash# umount /dev/ram7 bash# dd if=/dev/ram7 of=~/phase7-image bs=1k bash# gzip -9 ~/phase7-image

8.3.9. Copy the image to diskette

Insert the diskette labeled "root disk" into drive fd0.

bash# dd if=~/phase7-image.gz of=/dev/fd0 bs=1k