7zip/p7zip

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#!/bin/sh
# gzip-like CLI wrapper for p7zip
# version 3.0
#
# History
# 2.0 :
# - support for -filename, "file name"
# - p7zip file1 file2 ...
# 3.0 : (robert@debian.org, March 2016)
# - use 7za or 7zr, whichever one is available
# - refactor the script for better readability
# - remove `"$?" != 0 ' checks that do not work with `set -e'
# - use stderr for error reporting
# - add support for -c, -f, -k options
set -e
# detect 7z program to use
prg7z="`which 7za 2>/dev/null`" || \
prg7z="`which 7zr 2>/dev/null`" || \
{ echo "$0: cannot find neither 7za nor 7zr command" >&2; exit 1; }
# global options
f_compress=true
f_keep=false
f_force=false
f_tostdout=false
usage()
{
echo "Usage: $0 [options] [--] [ name ... ]"
echo ""
echo "Options:"
echo " -c --stdout --to-stdout output data to stdout"
echo " -d --decompress --uncompress decompress file"
echo " -f --force do not ask questions"
echo " -k --keep keep original file"
echo " -h --help print this help"
echo " -- treat subsequent arguments as file"
echo " names, even if they start with a dash"
echo ""
exit 0
}
has_7z_suffix()
{
case "$1" in
*.7z)
return 0
;;
*)
return 1
;;
esac;
}
make_tmp_file()
{
P7ZIPTMP="${TMP:-/tmp}"
mktemp "${P7ZIPTMP}/p7zip.XXXXXXXX"
}
check_not_a_tty()
{
if ! ${f_force} && ${f_compress} && tty <&1 >/dev/null ; then
echo "$0: compressed data not written to a terminal." >&2
echo "For help, type: $0 -h" >&2
exit 1
fi
}
compress_file()
{
file="$1"
if ! ${f_force} && has_7z_suffix "${file}"; then
echo "$0: $file already has the 7z suffix" >&2
exit 1
fi
# compress to stdout via temporary file
if ${f_tostdout}; then
check_not_a_tty
tmp="`make_tmp_file`"
trap "rm -f -- ${tmp}" 0
rm -f -- "${tmp}"
"${prg7z}" a -si -- "${tmp}" < "${file}" >/dev/null && cat "${tmp}" || \
{ echo "$0: failed to compress data to temporary file" >&2; exit 1; }
rm -f -- "${tmp}"
return 0
fi
# compress to a file
if ! ${f_force} && [ -e "${file}.7z" ]; then
echo "$0: destination file ${file}.7z already exists" >&2
exit 1
fi
rm -f -- "${file}.7z"
flags=""
${f_keep} || flags="$flags -sdel"
! ${f_force} || flags="$flags -y"
"${prg7z}" a $flags -- "${file}.7z" "${file}" || { rm -f -- "${file}.7z"; exit 1; }
}
decompress_file()
{
file="$1"
has_7z_suffix "${file}" || { echo "$0: ${file}: unknown suffix" >&2; exit 1; }
# decompress to stdout
if ${f_tostdout}; then
# The following `| cat' pipe shouldn't be needed, however it is here to
# trick 7z not to complain about writing data to terminal.
"${prg7z}" x -so -- "${file}" | cat || exit 1
return 0;
fi
flags=""
! ${f_force} || flags="$flags -y"
"${prg7z}" x $flags -- "${file}" || exit 1
# remove original file unless the archive contains more than one file
if ! ${f_keep} && "${prg7z}" l -- "${file}" 2>/dev/null | grep -q '^1 file,' 2>/dev/null; then
rm -f -- "${file}"
fi
}
process_file()
{
file="$1"
# check if file exists and is readable
[ -r "${file}" ] || { echo "$0: cannot read ${file}" >&2; exit 1; }
if ${f_compress}; then
compress_file "${file}"
else
decompress_file "${file}"
fi
}
process_stdin()
{
check_not_a_tty
tmp="`make_tmp_file`"
trap "rm -f -- ${tmp}" 0
if ${f_compress}; then
rm -f -- "${tmp}"
"${prg7z}" a -si -- "${tmp}" >/dev/null && cat -- "${tmp}" || exit 1
else # decompress
cat > "${tmp}"
# The following `| cat' pipe shouldn't be needed, however it is here to
# trick 7z not to complain about writing data to terminal.
"${prg7z}" x -so -- "${tmp}" | cat || exit 1
fi
rm -f -- "${tmp}"
}
## MAIN
# files and flags
while [ "$#" != "0" ] ; do
case "$1" in
-c|--stdout|--to-stdout)
f_tostdout=true
;;
-d|--decompress|--uncompress)
f_compress=false # decompressing
;;
-f|--force)
f_force=true
;;
-h|--help)
usage
;;
-k|--keep)
f_keep=true
;;
--)
shift
break
;;
-*)
echo "$0: ignoring unknown option $1" >&2
;;
*)
break
;;
esac
shift
done
# make sure they're present, before we screw up
for i in mktemp rm cat tty grep; do
if ! which $i >/dev/null ; then
echo "$0: $i: command not found" >&2
exit 1
fi
done
if [ "$#" = 0 ]; then
# compressing/decompressing using standard I/O
process_stdin
exit 0
fi
# only files now
while [ "$#" != "0" ] ; do
process_file "$1"
shift
done
exit 0