Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
msg=filename
else
msg=$@
fi
}
echo "Usage: `basename $0` "$msg""
Check_if_root () # Check if root running script.
{ # From "ex39.sh" example.
if [ "$UID" −ne "$ROOT_UID" ]
then
echo "Must be root to run this script."
exit $E_NOTROOT
fi
}
CreateTempfileName () # Creates a "unique" temp filename.
{ # From "ex51.sh" example.
prefix=temp
suffix=`eval date +%s`
Tempfilename=$prefix.$suffix
}
isalpha2 ()
# Tests whether *entire string* is alphabetic.
{ # From "isalpha.sh" example.
[ $# −eq 1 ] || return $FAILURE
}
case $1 in
*[!a−zA−Z]*|"") return $FAILURE;;
*) return $SUCCESS;;
esac
# Thanks, S.C.
abs ()
# Absolute value.
{ # Caution: Max return value = 256.
E_ARGERR=−999999
if [ −z "$1" ]
then
return $E_ARGERR
fi
# Need arg passed.
# Obvious error value returned.
if [ "$1" −ge 0 ]
# If non−negative,
then #
absval=$1
# stays as−is.
else
# Otherwise,
let "absval = (( 0 − $1 ))" # change sign.
fi
}
return $absval
tolower ()
# Converts string(s) passed as argument(s)
{ #+ to lowercase.
if [ −z "$1" ]
# If no argument(s) passed,
Chapter 34. Miscellany 348