From b00b2eb16bea6d5bb1a9889421de494bf30a142e Mon Sep 17 00:00:00 2001
From: Matteo Cypriani <mcy@lm7.fr>
Date: Wed, 11 Apr 2018 22:56:01 +0200
Subject: [PATCH] [cluster] minor improvements & shellcheck

---
 cluster/cluster-deploy.sh | 24 ++++++++++++++----------
 cluster/cluster-ping.sh   |  3 ++-
 cluster/cluster-run.sh    |  9 +++++----
 cluster/cluster-ssh.sh    | 15 ++++++++-------
 4 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/cluster/cluster-deploy.sh b/cluster/cluster-deploy.sh
index 961edc0..fb640ae 100755
--- a/cluster/cluster-deploy.sh
+++ b/cluster/cluster-deploy.sh
@@ -73,7 +73,7 @@ if [ "$DELETE" = "1" ] ; then
 fi
 
 # Ignore -P if rsync is going to be used
-if [ "$RSYNC" = "1" -a "$PARALLEL" = "1" ] ; then
+if [ "$RSYNC" = "1" ] && [ "$PARALLEL" = "1" ] ; then
   echo "Cannot transfer in parallel when using rsync: ignoring -P."
   PARALLEL=""
 fi
@@ -82,13 +82,13 @@ fi
 PSCP=$(command -v parallel-scp || command -v pscp.pssh || command -v pscp)
 PRSYNC=$(command -v parallel-rsync || command -v prsync)
 CLUSTERPING=$(command -v cluster-ping)
-if [ "$RSYNC" = "" -a "$PSCP" = "" ] ; then
+if [ -z "$RSYNC" ] && [ -z "$PSCP" ] ; then
   echo "Parallel SSH (pssh) is required for this script to work."
   exit 4
-elif [ "$PRSYNC" = "" ] ; then
+elif [ -z "$PRSYNC" ] ; then
   echo "Parallel rsync (prsync) is required for this script to work."
   exit 5
-elif [ "$CLUSTERPING" = "" ] ; then
+elif [ -z "$CLUSTERPING" ] ; then
   echo "cluster-ping (which should have been provided along with this"
   echo "script) is required for this script to work."
   exit 6
@@ -96,7 +96,7 @@ fi
 
 # Hosts' list file
 HOSTS_LIST_NAME="$1"
-if [ "$XDG_CONFIG_HOME" = "" ] ; then
+if [ -z "$XDG_CONFIG_HOME" ] ; then
   XDG_CONFIG_HOME="$HOME/.config"
 fi
 HOSTS="$XDG_CONFIG_HOME/cluster/${HOSTS_LIST_NAME}.lst"
@@ -108,7 +108,7 @@ if [ ! -f "$HOSTS" ] ; then
 fi
 
 # Login
-if [ "$LOGIN" != "" ] ; then
+if [ -n "$LOGIN" ] ; then
   echo "Login: $LOGIN"
   SSH_LOGIN="${LOGIN}@"
   LOGIN="-l $LOGIN"
@@ -116,14 +116,15 @@ fi
 
 # Test the connection to the first host and get the destination
 # directory (home directory of the remote user)
-FIRST_HOST=$($CLUSTERPING "$HOSTS_LIST_NAME" 2>/dev/null | sed -n "s/ is alive$//p" | head -n1)
-if [ "$FIRST_HOST" = "" ] ; then
+FIRST_HOST=$($CLUSTERPING "$HOSTS_LIST_NAME" 2>/dev/null \
+           | sed -n "s/ is alive$//p" | head -n1)
+if [ -z "$FIRST_HOST" ] ; then
   echo "None of the remote hosts is alive."
   exit 7
 fi
 echo "Testing connection to $FIRST_HOST..."
-DEST_DIR="$(ssh ${SSH_LOGIN}${FIRST_HOST} 'echo $HOME' 2>/dev/null)"
-if [ "$DEST_DIR" = "" ] ; then
+DEST_DIR="$(ssh "${SSH_LOGIN}${FIRST_HOST}" 'echo $HOME' 2>/dev/null)"
+if [ -z "$DEST_DIR" ] ; then
   echo "Cannot connect to the first alive host. Aborting."
   exit 7
 fi
@@ -131,6 +132,7 @@ echo "Destination directory: $DEST_DIR"
 
 # Transfer the files in parallel...
 if [ "$PARALLEL" = "1" ] ; then
+  # shellcheck disable=SC2086
   exec $PSCP -r $LOGIN -h "$HOSTS" -- "$@" "$DEST_DIR"
 fi
 
@@ -142,8 +144,10 @@ for FILE in "$@" ; do
     continue
   fi
   if [ "$RSYNC" = "1" ] ; then
+    # shellcheck disable=SC2086
     $PRSYNC -a $DELETE $LOGIN -h "$HOSTS" -- "$FILE" "$DEST_DIR"
   else
+    # shellcheck disable=SC2086
     $PSCP -r $LOGIN -h "$HOSTS" -- "$FILE" "$DEST_DIR"
   fi
 done
diff --git a/cluster/cluster-ping.sh b/cluster/cluster-ping.sh
index 894d0d2..c4df121 100755
--- a/cluster/cluster-ping.sh
+++ b/cluster/cluster-ping.sh
@@ -17,7 +17,7 @@ if [ $# -ne 1 ] ; then
 fi
 
 # Hosts' list file
-if [ "$XDG_CONFIG_HOME" = "" ] ; then
+if [ -z "$XDG_CONFIG_HOME" ] ; then
   XDG_CONFIG_HOME="$HOME/.config"
 fi
 HOSTS="$XDG_CONFIG_HOME/cluster/$1.lst"
@@ -28,4 +28,5 @@ if [ ! -f "$HOSTS" ] ; then
 fi
 
 # Go!
+# shellcheck disable=SC2046
 exec fping $(cat "$HOSTS") 2>/dev/null
diff --git a/cluster/cluster-run.sh b/cluster/cluster-run.sh
index 5e12a41..023c71c 100755
--- a/cluster/cluster-run.sh
+++ b/cluster/cluster-run.sh
@@ -19,7 +19,7 @@ print_usage()
 
 # Do we have at least a host list and a command?
 if [ $# -lt 2 ] ; then
-  print_usage
+  print_usage >&2
   exit 1
 fi
 
@@ -38,13 +38,13 @@ fi
 
 # Check dependencies
 PSSH=$(command -v parallel-ssh || command -v pssh)
-if [ "$PSSH" = "" ] ; then
+if [ -z "$PSSH" ] ; then
   echo "Parallel SSH (pssh) is required for this script to work."
   exit 4
 fi
 
 # Hosts' list file
-if [ "$XDG_CONFIG_HOME" = "" ] ; then
+if [ -z "$XDG_CONFIG_HOME" ] ; then
   XDG_CONFIG_HOME="$HOME/.config"
 fi
 HOSTS="$XDG_CONFIG_HOME/cluster/$1.lst"
@@ -56,11 +56,12 @@ if [ ! -f "$HOSTS" ] ; then
 fi
 
 # Login
-if [ "$LOGIN" != "" ] ; then
+if [ -n "$LOGIN" ] ; then
   echo "Login: $LOGIN"
   LOGIN="-l $LOGIN"
 fi
 
 echo "Command:" "$@"
 
+# shellcheck disable=SC2086
 exec $PSSH --print $LOGIN -h "$HOSTS" -- "$@"
diff --git a/cluster/cluster-ssh.sh b/cluster/cluster-ssh.sh
index 6cb6d16..d6b81bb 100755
--- a/cluster/cluster-ssh.sh
+++ b/cluster/cluster-ssh.sh
@@ -35,25 +35,26 @@ elif [ $# -ne 1 ] ; then
 fi
 
 # Hosts' list file
-if [ "$XDG_CONFIG_HOME" = "" ] ; then
+if [ -z "$XDG_CONFIG_HOME" ] ; then
   XDG_CONFIG_HOME="$HOME/.config"
 fi
-HOSTS="$XDG_CONFIG_HOME/cluster/$1.lst"
+HOSTS_FILE="$XDG_CONFIG_HOME/cluster/$1.lst"
 shift
-echo "Using file '$HOSTS' as hosts' list."
-if [ ! -f "$HOSTS" ] ; then
+echo "Using file '$HOSTS_FILE' as hosts' list."
+if [ ! -f "$HOSTS_FILE" ] ; then
   echo "The hosts' list file doesn't exist or is not a regular file."
   exit 2
 fi
 
 # Login
-if [ "$LOGIN" != "" ] ; then
+if [ -n "$LOGIN" ] ; then
   echo "Login: $LOGIN"
   LOGIN="${LOGIN}@"
 fi
 
 # Create the screen tabs
-for HOST in $(cat "$HOSTS") ; do
+while read -r HOST ; do
   SSH="ssh ${LOGIN}${HOST}"
+  # shellcheck disable=SC2086
   screen -t "$SSH" $SSH
-done
+done <"$HOSTS_FILE"