Bash-Beginners-Guide

Bash Guide for Beginners
# This is a simple script that you can use for converting text into HTML.
# First we take out all newline characters, so that the appending only happens
# once, then we replace the newlines.
echo "converting $1..."
SCRIPT="/home/sandy/scripts/script.sed"
NAME="$1"
TEMPFILE="/var/tmp/sed.$PID.tmp"
sed "s/\n/^M/" $1 | sed -f $SCRIPT | sed "s/^M/\n/" > $TEMPFILE
mv $TEMPFILE $NAME
echo "done."
sandy ~>
$1 holds the first argument to a given command, in this case the name of the file to convert:
sandy ~> cat test
line1
line2
line3
More on positional parameters in Chapter 7.
sandy ~> txt2html.sh test
converting test...
done.
sandy ~> cat test
sed generated html
line1
line2
line3
sandy ~>
This is not really how it is done; this example just demonstrates sed capabilities. See Section 6.3 for a more
decent solution to this problem, using awk BEGIN and END constructs.
Easy sed
Advanced editors, supporting syntax highlighting, can recognize sed syntax. This can be a great help if
you tend to forget backslashes and such.
5.4. Summary
The sed stream editor is a powerful command line tool, which can handle streams of data: it can take input
lines from a pipe. This makes it fit for non-interactive use. The sed editor uses vi-like commands and accepts
regular expressions.
The sed tool can read commands from the command line or from a script. It is often used to perform
Chapter 5. The GNU sed stream editor 67