UNIX for Dummies Questions & Answers

#!/usr/bin/env sh

# @(#) s1       Demonstrate one way to get a ".", dot into a file with ed.

set -o nounset
echo

debug=":"
debug="echo"

## Use local command version for the commands in this demonstration.

echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version bash ed

echo

# Create a file.
cat >data1 <<'EOF'
Hi.
Goodbye.
EOF

echo " Input file:"
cat data1

echo
echo " Conversation with ed:"
ed data1 <<'EOF'
1
a
.x
.
s/x//
w
q
EOF

echo
echo " Results from ed"
cat data1

exit 0

% ./s1

(Versions displayed with local utility "version")
GNU bash 2.05b.0
GNU ed version 0.2

 Input file:
Hi.
Goodbye.

 Conversation with ed:
13
Hi.
15

 Results from ed
Hi.
.
Goodbye.