Shell Programming Case Study #1

#!/bin/sh
# case study #1: show certain file characteristics in nice columns

# assume we want to output the filename, then owner,
# then size.
# show these in nice columns
# do this for all regular files in the $1 dir and
# all subdir's (recursively)

DIR=$1  # save cmd line arg before using set

USAGE="Usage: `basename $0` directory"

if [ ! -d "$DIR" ]
then
   echo "Error: $DIR is not a valid directory" >&2
   echo $USAGE >&2
   exit 1
fi

echo "Starting dir is $DIR\n"

# show column headings
FNSZ=25
OWNSZ=10
BYTSZ=10
BLOCKSZ=9

printf "%-${FNSZ}s %-${OWNSZ}s %${BYTSZ}s %${BLOCKSZ}s\n\n" "filename" "owner" "bytes" "blocks"
###printf "%-25s %-10s %10s %9s\n\n" "filename" "owner" "bytes" "blocks"

# show data
for FILE in `find $DIR -type f 2>/dev/null`
do
   set -- `ls -ld $FILE`

      # set will assign values to the positional parameters: $1, $2 etc
      # Example output for ls -l:
      #
      # -rw-r--r--   1 stevemor instrctr     167 Oct 16 16:06 class1
      # $1          $2 $3       $4           $5  $6  $7 $8    $9
      #
      # Add -- after set or any cmd if first arg might start w/ -

   BLOCKS=`echo "scale=2;$5/512"|bc`
   printf "%-${FNSZ}s %-${OWNSZ}s %${BYTSZ}d %$BLOCKSZ.2f\n" $9 $3 $5 $BLOCKS
   ###printf "%-25s %-10s %10d %9.2f\n" $9 $3 $5 $BLOCKS

      # Added dash (-) to left justify the filename and owner
      # The size in bytes and blocks do not contain a dash (-) so they are
      #   right justified.
      # Right justify (no dash) the sizes since that makes numbers easier
      # to compare.
      # Each field specification starts with a % sign
      #    end in s for string
      #    end in d for decimal integer
      #    end in f for floating point
      # %9.2f reserves 9 char positions
      #    2 to the right of the decimal pt
      #    1 for the decimal pt itself
      #    6 to the left of the decimal pt
      # Note: if the actual value exceeds the size specification,
      #    the whole value will be printed anyway
      #    so your columns will not line up.

done

Starting dir is /tmp

filename                  owner           bytes    blocks

/tmp/daemonstat.any.80    root             3676      7.17
/tmp/daemonstat.any.620   root             3676      7.17
/tmp/f1                   stevemor          132      0.25
/tmp/f2                   stevemor           94      0.18
/tmp/Ex05831              g4b                 0      0.00
/tmp/mori/f1              stevemor         1895      3.70
/tmp/mori/f2              stevemor        41895     81.82
/tmp/Rx05831              g4b              4096      8.00
/tmp/Ex07739              h8j              6144     12.00
/tmp/Rx07739              h8j              3072      6.00
/tmp/pga006lF             h8j               959      1.87
/tmp/Ex09097              a8y              6144     12.00
/tmp/Ex16198              h8j                 0      0.00
/tmp/Rx09097              a8y              2048      4.00
/tmp/pga002kK             h4e                 0      0.00
/tmp/hpnpcfg.log          root              848      1.65
/tmp/pga002w3             y6g              2180      4.25
/tmp/Ex09263              stevemor         8192     16.00
/tmp/Rx09263              stevemor         3072      6.00
/tmp/dograde3             stevemor         1997      3.90