useful bash shell functions

cdtemp

Possibly the all-time cmrg favorite bash function:

# create temporary directory, and cd to it,
# copying in all specified files
function cdtemp {
    local TD=$(mktemp -d -t cdtemp.XXXXXX)
    if [ $TD ] ; then
	(
	    [ $1 ] && cp -a $@ "$TD"
	    cd "$TD" && "$SHELL"
	) && rm -rf "$TD"
    fi
}
export -f cdtemp

hsrv

# make a TCP connection to a standard service, using readline to track your history: 
# example usage: 
#   hsrv http www.example.com
# you can specify an alternate port by appending it:
#   hsrv smtp mailserver.example.com 2525
# FIXME: which services besides smtp need the crnl option?
function hsrv() {
    [ -d "$HOME/.histories" ] || mkdir "$HOME/.histories"
    local extraopts=""
    [ "smtp" == "$1" ] && extraopts=",crnl"
    socat "READLINE,history=$HOME/.histories/$1$extraopts" "TCP4:$2:${3:-$1}"
}
export -f hsrv

meat

# output uncommented (with #), non-blank lines of file
function meat {
    grep -v -e '^[[:space:]]*#' -e '^$' $@
}
export -f meat

psg

# grep process list
function psg {
    ps -eFH | head -1
    ps -eFH | grep "$@" | cat
}
export -f psg

lsstale

# count the number of open files with stale path inodes, and sort
function lsstale {
    sudo lsof | grep 'path inode' | cut -d ' ' -f 1 | sort | uniq -c
}
export -f lsstale

cutline

# cutout lines of a file
function cutline {
    if [ "$3" ] ; then
        cat "$1" | head --line="$3" | tail -$(( $3 - $2 + 1 ))
    else
        cat "$1" | head --line="$2" | tail -1
    fi
}
export -f cutline

watcha

# repeat a command indefinitely
function watcha {
    while true; do 
        if "$@"; then
            echo -e -n \'\a\'
        fi
        sleep 1
    done
}
export -f watcha