Advanced Bash−Scripting Guide

Appendix A. Contributed Scripts
These scripts, while not fitting into the text of this document, do illustrate some interesting shell programming
techniques. They are useful, too. Have fun analyzing and running them.
Example A−1. manview: Viewing formatted manpages
#!/bin/bash
# manview.sh: Formats the source of a man page for viewing.
# This is useful when writing man page source and you want to
#+ look at the intermediate results on the fly while working on it.
E_WRONGARGS=65
if [ −z "$1" ]
then
echo "Usage: `basename $0` filename"
exit $E_WRONGARGS
fi
groff −Tascii −man $1 | less
# From the man page for groff.
# If the man page includes tables and/or equations,
# then the above code will barf.
# The following line can handle such cases.
#
# gtbl < "$1" | geqn −Tlatin1 | groff −Tlatin1 −mtty−char −man
#
# Thanks, S.C.
exit 0
Example A−2. mailformat: Formatting an e−mail message
#!/bin/bash
# mail−format.sh: Format e−mail messages.
# Gets rid of carets, tabs, also fold excessively long lines.
# =================================================================
# Standard Check for Script Argument(s)
ARGS=1
E_BADARGS=65
E_NOFILE=66
if [ $# −ne $ARGS ] # Correct number of arguments passed to script?
then
echo "Usage: `basename $0` filename"
exit $E_BADARGS
fi
if [ −f "$1" ]
then
file_name=$1
# Check if file exists.
Appendix A. Contributed Scripts 368