systemadmin: refactor plugin and fix README (#7295)

plugins/systemadmin/systemadmin.plugin.zsh

@@ -12,14 +12,6 @@
 #
 # ------------------------------------------------------------------------------
 
-function retval() {
-    if [[ -z $1 ]];then
-        echo '.'
-    else
-        echo $1
-    fi
-}
-
 function retlog() {
     if [[ -z $1 ]];then
         echo '/var/log/nginx/access.log'
@@ -29,8 +21,8 @@ function retlog() {
 }
 
 alias ping='ping -c 5'
-alias clr='clear;echo "Currently logged in on $(tty), as $USER in directory $PWD."'
-alias path='echo -e ${PATH//:/\\n}'
+alias clr='clear; echo Currently logged in on $TTY, as $USER in directory $PWD.'
+alias path='print -l $path'
 alias mkdir='mkdir -pv'
 # get top process eating memory
 alias psmem='ps -e -orss=,args= | sort -b -k1,1n'
@@ -43,10 +35,10 @@ alias hist10='print -l ${(o)history%% *} | uniq -c | sort -nr | head -n 10'
 
 # directory LS
 dls () {
-    ls -l | grep "^d" | awk '{ print $9 }' | tr -d "/"
+    print -l *(/)
 }
 psgrep() {
-    ps aux | grep "$(retval $1)" | grep -v grep
+    ps aux | grep "${1:-.}" | grep -v grep
 }
 # Kills any process that matches a regexp passed to it
 killit() {
@@ -54,10 +46,10 @@ killit() {
 }
 
 # list contents of directories in a tree-like format
-if [ -z "\${which tree}" ]; then
-  tree () {
-      find $@ -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'
-  }
+if ! (( $+commands[tree] )); then
+    tree () {
+        find $@ -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'
+    }
 fi
 
 # Sort connection state
@@ -97,7 +89,7 @@ syn20() {
 
 # Printing process according to the port number
 port_pro() {
-    netstat -ntlp | grep "$(retval $1)" | awk '{print $7}' | cut -d/ -f1
+    netstat -ntlp | grep "${1:-.}" | awk '{print $7}' | cut -d/ -f1
 }
 
 # top10 of gain access to the ip address
@@ -134,7 +126,7 @@ httpstatus() {
 
 # Delete 0 byte file
 d0() {
-    find "$(retval $1)" -type f -size 0 -exec rm -rf {} \;
+    find "${1:-.}" -type f -size 0 -exec rm -rf {} \;
 }
 
 # gather external ip address