length_in_centimeters
The first argument is referred to as $1 , the second as $2 and so on. The total number of arguments is stored in $# .
Check out Section 7.2.5 for a more elegant way to print usage messages.
7.2.1.4. Testing that a file exists
This test is done in a lot of scripts, because there's no use in starting a lot of programs if you know they're not going to work:
#!/bin/bash
# This script gives information about a file.
FILENAME="$1"
echo "Properties for $FILENAME:"
if [ -f $FILENAME ]; then
echo "Size is $(ls -lh $FILENAME | awk '{ print $5 }')"
echo "Type is $(file $FILENAME | cut -d":" -f2 -)"
echo "Inode number is $(ls -i $FILENAME | cut -d" " -f1 -)"
echo "$(df -h $FILENAME | grep -v Mounted | awk '{ print "On",$1", \
which is mounted as the",$6,"partition."}')"
else
echo "File does not exist."
fi
Note that the file is referred to using a variable; in this case it is the first argument to the script. Alternatively, when no arguments are given, file locations are usually stored in variables at the beginning of a script, and their content is referred to using these variables. Thus, when you want to change a file name in a script, you only need to do it once.
