Various bash snippets I've used in scripts

bash-snippets.bash

#!/bin/bash 

# disable builtin echo so we can use '-en'
enable -n echo

SCRIPT=$(basename "$0")
SCRIPT_DIR=$(dirname "$0")
echo "$SCRIPT running from $SCRIPT_DIR"

# Determine if we're interactive or not
# is_interactive() { test -t 0; }
use_ansi() { test -t 1; }


# only output colors if our output is to terminal
if use_ansi ; then
    GREEN="\033[0;32m"
    RED="\033[0;31m"
    YELLOW="\033[0;33m"
    BOLD_WHITE="\033[1;37m"
    CLEAR="\033[0m"
else
    GREEN=""
    RED=""
    YELLOW=""
    BOLD_WHITE=""
    CLEAR=""
fi

# ANSI color output helpers
green() { echo -en "${GREEN}"$@"${CLEAR}"; }
red() { echo -en "${RED}"$@"${CLEAR}"; }
yellow() { echo -en "${YELLOW}"$@"${CLEAR}"; }
hl() { echo -en "${BOLD_WHITE}"$@"${CLEAR}"; }

# output stuff to terminal
log() { echo -en "$@"; }
logfmt() { printf "$@"; }

# Extended RegExp matching on arguments
# $1 = regex pattern
# $@... = remaining args as string to match against
matches() {
    local pat=$1; shift
    echo "$@" | grep -qEi "$pat" >/dev/null 2>&1
}

pass() {
    local check="✔"
    green $check
}

fail() {
    local x="✘"
    red $x
}

# trim leading/trailing whitespace in string
trim() {
    echo "$@" | awk '{ gsub(/^ +| +$/,"") }{ print $0 }'
}

# repeat character $1 for $2 times
repeat() {
   echo $(printf "%${2}s" |tr " " "$1")
}

# is_available COMMAND [TEST]
# Check if 'command' is available and if passed
# execute TEST as well
# returns command line status of both
is_available() {
    local cmd=$1; shift 
    local res=0
    hash $cmd >/dev/null 2>&1 || { local res=1; }
    if [ $# -ge 1 ]; then
        $@ >/dev/null 2>&1 || { local res=2; }
    fi
    # echo -n $res
    return $res
}

filesize() {
    local filename=$1; shift
    echo $(du -k "$filename" | cut -f1)
}

truncate() {
    local len=$1; shift;
    echo "$*" | awk -v len=$len '{ if (length($0) > len) print substr($0, 1, len-3) "..."; else print; }'
}

escape() {
    echo "$1" | sed 's/\([\.\$\*]\)/\\\1/g'
}

escapeSlashes() {
    echo "$@" | sed 's/\\/\\\\/g'
}

# Convert UCS-2/UTF-16 with BOM file encoding to UTF-8 w/o BOM
# ucs2utf8 DIR FILE_PATTERN
# where 
#   - DIR is the root directory to find files for conversion
#   - FILE_PATTERN is `find` pattern to match file names
ucs2utf8() {
    local count=0
    local converted=0
    local DIR=$1
    local FILE_PAT=$2

    # Ensure we can handle filenames w/ spaces in them
    local oldIFS=$IFS
    IFS=$(echo -en "\n\b")

    for file in $(find $DIR -name $FILE_PAT 2>/dev/null); do
        count=$((count + 1))
        # If it has a BOM and first character after is nul (00), convert it
        if od -x "$file" | head -1 | cut -d' ' -f 2,3 | grep "feff 00" >/dev/null 2>&1; then
            log "Converting $(hl ${file}) to UTF-8........"
            converted=$((converted + 1))
            local tmp="${file}.tmp"
            mv "${file}" "${tmp}"
            iconv -c -f UCS-2 -t UTF-8 "${tmp}" > "${file}"
            rm "${tmp}"
            log "$(pass)\n"
        fi
    done
    IFS=$oldIFS
    echo "$converted/$count"
}


while IFS= read -r line
do
    if matches "^if\s+" $line; then
        log $(hl "found: ") $(green $line) "\n"
        log $(yellow "A warning line...")"\n"
        log $(red "An error line...")"\n"
    fi
done < t.sh

logfmt "%20.20b %20.20b" $(green "test") $(yellow "again")