added some stuff

lib/bin/is

@@ -0,0 +1,127 @@
+#!/bin/bash
+#
+# Copyright (c) 2016 Józef Sokołowski
+# Distributed under the MIT License
+#
+# For most current version checkout repository:
+# https://github.com/qzb/is.sh
+#
+
+is() {
+    if [ "$1" == "--help" ]; then
+        cat << EOF
+Conditions:
+  is equal VALUE_A VALUE_B
+  is matching REGEXP VALUE
+  is substring VALUE_A VALUE_B
+  is empty VALUE
+  is number VALUE
+  is gt NUMBER_A NUMBER_B
+  is lt NUMBER_A NUMBER_B
+  is ge NUMBER_A NUMBER_B
+  is le NUMBER_A NUMBER_B
+  is file PATH
+  is dir PATH
+  is link PATH
+  is existing PATH
+  is readable PATH
+  is writeable PATH
+  is executable PATH
+  is available COMMAND
+  is older PATH_A PATH_B
+  is newer PATH_A PATH_B
+  is true VALUE
+  is false VALUE
+
+Negation:
+  is not equal VALUE_A VALUE_B
+EOF
+        exit
+    fi
+
+    if [ "$1" == "--version" ]; then
+        echo "is.sh 1.1.0"
+        exit
+    fi
+
+    local condition="$1"
+    local value_a="$2"
+    local value_b="$3"
+
+    if [ "$condition" == "not" ]; then
+        shift 1
+        ! is "${@}"
+        return $?
+    fi
+
+    if [ "$condition" == "a" ] || [ "$condition" == "an" ] || [ "$condition" == "the" ]; then
+        shift 1
+        is "${@}"
+        return $?
+    fi
+
+    case "$condition" in
+        file)
+            [ -f "$value_a" ]; return $?;;
+        dir|directory)
+            [ -d "$value_a" ]; return $?;;
+        link|symlink)
+            [ -L "$value_a" ]; return $?;;
+        existent|existing|exist|exists)
+            [ -e "$value_a" ]; return $?;;
+        readable)
+            [ -r "$value_a" ]; return $?;;
+        writeable)
+            [ -w "$value_a" ]; return $?;;
+        executable)
+            [ -x "$value_a" ]; return $?;;
+        available|installed)
+            which "$value_a"; return $?;;
+        empty)
+            [ -z "$value_a" ]; return $?;;
+        number)
+            echo "$value_a" | grep -E '^[0-9]+(\.[0-9]+)?$'; return $?;;
+        older)
+            [ "$value_a" -ot "$value_b" ]; return $?;;
+        newer)
+            [ "$value_a" -nt "$value_b" ]; return $?;;
+        gt)
+            is not a number "$value_a"      && return 1;
+            is not a number "$value_b"      && return 1;
+            awk "BEGIN {exit $value_a > $value_b ? 0 : 1}"; return $?;;
+        lt)
+            is not a number "$value_a"      && return 1;
+            is not a number "$value_b"      && return 1;
+            awk "BEGIN {exit $value_a < $value_b ? 0 : 1}"; return $?;;
+        ge)
+            is not a number "$value_a"      && return 1;
+            is not a number "$value_b"      && return 1;
+            awk "BEGIN {exit $value_a >= $value_b ? 0 : 1}"; return $?;;
+        le)
+            is not a number "$value_a"      && return 1;
+            is not a number "$value_b"      && return 1;
+            awk "BEGIN {exit $value_a <= $value_b ? 0 : 1}"; return $?;;
+        eq|equal)
+            [ "$value_a" = "$value_b" ]     && return 0;
+            is not a number "$value_a"      && return 1;
+            is not a number "$value_b"      && return 1;
+            awk "BEGIN {exit $value_a == $value_b ? 0 : 1}"; return $?;;
+        match|matching)
+            echo "$value_b" | grep -xE "$value_a"; return $?;;
+        substr|substring)
+            echo "$value_b" | grep -F "$value_a"; return $?;;
+        true)
+            [ "$value_a" == true ] || [ "$value_a" == 0 ]; return $?;;
+        false)
+            [ "$value_a" != true ] && [ "$value_a" != 0 ]; return $?;;
+    esac > /dev/null
+
+    return 1
+}
+
+if is not equal "${BASH_SOURCE[0]}" "$0"; then
+    export -f is
+else
+    is "${@}"
+    exit $?
+fi