X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=lib.sh;h=88b7b98a26f2ba84cf2c141191bc296dbac48ddc;hb=8c731331a353d82adc61a81bd3cb92e79f3c2dc8;hp=582e1cffe66b1f440dcec0744c08f336fffeb8ea;hpb=f8404b8badbb07ea82dd043127838fd7ef562ba9;p=config%2Fdotfiles.git

diff --git a/lib.sh b/lib.sh
index 582e1cf..88b7b98 100644
--- a/lib.sh
+++ b/lib.sh
@@ -11,6 +11,25 @@ unset LS_COLORS
 m4=`which m4`
 
 
+# Check if the given program is installed. Returns 0 if it exists, 1
+# otherwise; so it can be used in if.
+installed() {
+    which $1 | grep -E '^/' > /dev/null
+}
+
+# Prints the current OS. Supported are Debian (debian) and Mac OS X (darwin)
+# at the moment. If an unsupported OS is used an error is printed.
+os() {
+    if [ -f /etc/debian_version ]; then
+        echo debian
+    elif [ x`uname` = xDarwin ]; then
+        echo darwin
+    else
+        echo unsupported OS! >&2
+        return 1
+    fi
+}
+
 # Creates a symbolic link for file $1 in dirname of $2 with name of basenmae
 # $2.
 #
@@ -54,6 +73,11 @@ link() {
 # to $1 with a warning at the beginning to not edit the generated file.
 #
 # All arguments (except the first which is the filename) are passed to m4.
+#
+# The following macros are defined: IF and FI. Example:
+#     IF(OS, debian)
+#         ...
+#     FI
 m4() {
     # First argument is file name.
     file=$1
@@ -69,7 +93,11 @@ m4() {
 
     # Process $1.m4 with m4 using the given options.
     echo "m4(): generating '$file' from '$file.m4' with options '$*'"
-    $m4 $* $file.m4 >> $file
+    # Add useful macros.
+    (echo "define(\`IF', \`ifelse(\`\$1', \`\$2',dnl')dnl
+define(\`FI', \`)dnl')dnl";
+        # Run the file (and the default macros) through m4.
+        cat $file.m4) | $m4 $* >> $file
 
     unset file
 }