em

#!/bin/sh
# EM --- emacsclient wrapper
# Emacs client wrapper support (sudo) editing of single files and diff mode.

# A POSIX variable
# Reset in case getopts has been used previously in the shell.
OPTIND=1

usage() {
    cat << EOF
Usage: $0 [-scdtxh] file(s) [optional emacs args]

Emacs client launcher wrapper.

OPTIONS:
   -s    Edit as sudo
   -c    Execute file checks
   -d    Diff two files
   -t    Run in terminal
   -x    Run in new x window
   -h    Print help

$0 file1
$0 -s -d -c file1 file2

EOF

}

fchecks=false
as_root=false
workdir=$(pwd)
dffmode=false

# Check if command is run in terminal, set defaults
if [ -t 0 ]; then
    in_term=true
else
    in_term=false
fi

# Check if file exists or is empty
file_check() {
    [ -f "$1" ] || { echo "$1 doesn't exist"; exit 1; }
    [ -s "$1" ] || { echo "$1 is empty"; exit 1; }
}

# Make the filename absolute (if needed) and add sudo (if req)
file_name() {
    # If file needs to be edited as root
    if [ "$as_root" = true ]; then
        sudopre="/sudo::"
    else
        sudopre=""
    fi
    # Check if path is relative or abs, make abs.
    if [[ "${1:0:1}" == / || "${1:0:1}" == ~[/a-z] ]]; then
        echo "$sudopre$1"
    else
        echo "$sudopre$workdir/$1"
    fi
}

# Check whether two files are the same (diff mode only)
file_ident_check() {
    cmp --silent $1 $2 && { echo "$1 and $2 are the same"; exit 1; }
}

# Process all options
while getopts 'scdtxh:' opt; do
        case "$opt" in
            s)
                as_root=true
                ;;
            c)
                fchecks=true
                ;;
            d)
                dffmode=true
                ;;
            t)
                in_term=true
                ;;
            x)
                in_term=false
                ;;
            h)
                usage
                exit 0;;
            /?)
                echo "Unrecognized command: $OPTARG"
                usage
                exit 1
                ;;
        esac
done
shift `expr $OPTIND - 1`

# Do file checks based on mode
if [ "$fchecks" = true ]; then
    file_check $1
    if [ "$dffmode" = true ]; then
        file_check $2
        file_ident_check $1 $2
    fi
fi

# Create emacs arguments for opening files
if [ "$dffmode" = true ]; then
    emargs="(ediff-files \"$(file_name $1)\" \"$(file_name $2)\")"
    shift `expr 2`
else
    emargs="(find-file \"$(file_name $1)\")"
    shift `expr 1`
fi

# Call emacs client in terminal or root
if [ "$in_term" = true ]; then
    emacsclient -t --eval "${emargs}" ${@}
else
    emacsclient -nc --eval "${emargs}" ${@}
fi