Some useful bash helper functions

functions.sh

#!/bin/bash 

##
## indir - execute given command ($2) in 
##         target directory ($1) with arguments ($3..N) 
##
function indir {
    if [[ "$1" = "" ]] || [[  "$2" = "" ]]; then 
	echo "[i] Usage: indir <target_dir> <command> <arg1> .. <argN>"
	return 1
    fi

    if [ ! -d "$1" ] || [ ! -x "$1" ]; then
        echo "[-] cannot change dir into $1"
	return 1
    fi 
    
    pushd "$1" > /dev/null
    if [[ "$?" != "0" ]]; then
        echo "[-] pushd failed!"
       	return 1
    fi
    
    shift
    $@
    
    popd > /dev/null
    if [[ "$?" != "0" ]]; then
 	echo "[-] popd failed!" 
	return 1
    fi 

    return 0
}

##
## ppwd - a pwd with file support 
## (return full-absolute-path of given file)
##
function ppwd {
    if [[ "$1" = "" ]]; then
       pwd
       return $?
    fi
    mydir=$(indir `dirname $1` pwd)
    myfn=$(basename $1)
    echo ${mydir}/${myfn}
    return 0
}
##
## isscreen - check if shell is inside a screen session
##
alias isscreen="([[ \"$STY\" = \"\" ]] && echo \"NO SCREEN SESSION\" ) || echo \"YES SCREEN SESSION\""

##
## is_int - check for integer inside string
##
function is_int() { 
( [[ "$1" = "$(echo $1 | awk '{print strtonum($0)}')" ]] && \
	return 0 ) || return 1;
}