Working with compressed files

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Linux usually provides a couple of command piping gzip

zgrep, zcat, zdiff, zless, zmore, zegrep,...

Here is a simple extension of tail and head for zipped files, that you can call ztail and zhead (example is for tail, replace "tail" with "head" everywhere to get zhead) and add to your own /bin directory:

Caution:

very basic version, works when the options starts with '-' so it works with '-n10' but fails with '-n 10'. Should be easily improved...

#!/bin/bash                                                                                                                                                  

# This program is free software; you can redistribute it and/or modify                                                                                       
# it under the terms of the GNU General Public License as published by                                                                                       
# the Free Software Foundation; either version 2 of the License, or                                                                                          
# (at your option) any later version.                                                                                                                        

# This program is distributed in the hope that it will be useful,                                                                                            
# but WITHOUT ANY WARRANTY; without even the implied warranty of                                                                                             
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                                                                              
# GNU General Public License for more details.                                                                                                               

# You should have received a copy of the GNU General Public License along                                                                                    
# with this program; if not, write to the Free Software Foundation, Inc.,                                                                                    
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.                                                                                                

# based on zless                                                                                                                                             

PATH=${GZIP_BINDIR-'/bin'}:$PATH

version="ztail 0.1                                                                                                                                           
Copyright (C) 2007, Free Software Foundation, Inc. <http://fsf.org/>                                                                                         
This is free software.  You may redistribute copies of it under the terms of                                                                                 
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.                                                                                       
There is NO WARRANTY, to the extent permitted by law.                                                                                                        
                                                                                                                                                             
Written by Guillaume Roux."

usage="Usage: $0 [OPTIONS]... [FILES]...                                                                                                                     
                                                                                                                                                             
Same as the 'tail' command, but operate on the uncompressed contents of any compressed FILEs.                                                                
Options are the same as for 'tail'."

case $1 in
--help)    exec echo "$usage";;
-h)        exec echo "$usage";;
--version) exec echo "$version";;
esac

options=""
count=0
for i in $@; do
str="$i"
if test -f $i && [ ${str:(-3)} = ".gz" ]; then
    files[++count]=$str
else
    if [ ${str:0:1} = "-" ] && [ $str != "-v" ] && [ $str != "--verbose" ]; then
	options=$options"$i "
    elif [ $str != "-v" ] && [ $str != "--verbose" ]; then
        echo -ne "***Warning: $i is neither a regular zip file or a regular option***\n\n"
    fi
fi
done

if [ $count -gt 0 ]; then
    if [ $count -eq 1 ]; then
        exec gzip -cd ${files[1]} | tail $options
    else
        for j in `seq 1 $count`; do
            echo "==>"${files[j]}"<=="
            exec gzip -cd ${files[j]} | tail $options
        done
    fi
else
    echo -ne "***Warning: no regular zip files given***\n\n"
    exec echo "$usage"
fi