diff --git a/bash_completion b/bash_completion
index 4e48c98d..8619676c 100644
--- a/bash_completion
+++ b/bash_completion
@@ -578,7 +578,7 @@ _expand()
 
 # This function completes on process IDs.
 # AIX and Solaris ps prefers X/Open syntax.
-[ $UNAME = SunOS -o $UNAME = AIX ] &&
+[[ $UNAME == SunOS || $UNAME == AIX ]] &&
 _pids()
 {
     COMPREPLY=( $( compgen -W '$( command ps -efo pid | sed 1d )' -- "$cur" ))
@@ -590,7 +590,7 @@ _pids()
 
 # This function completes on process group IDs.
 # AIX and SunOS prefer X/Open, all else should be BSD.
-[ $UNAME = SunOS -o $UNAME = AIX ] &&
+[[ $UNAME == SunOS || $UNAME == AIX ]] &&
 _pgids()
 {
     COMPREPLY=( $( compgen -W '$( command ps -efo pgid | sed 1d )' -- "$cur" ))
@@ -602,7 +602,7 @@ _pgids()
 
 # This function completes on process names.
 # AIX and SunOS prefer X/Open, all else should be BSD.
-[ $UNAME = SunOS -o $UNAME = AIX ] &&
+[[ $UNAME == SunOS || $UNAME == AIX ]] &&
 _pnames()
 {
     COMPREPLY=( $( compgen -W '$( command ps -efo comm | \
@@ -888,8 +888,7 @@ _chgrp()
     fi
 
     # first parameter on line or first since an option?
-    if [ $COMP_CWORD -eq 1 ] && [[ "$cur" != -* ]] || \
-        [[ "$prev" == -* ]]; then
+    if [[ $COMP_CWORD -eq 1 && "$cur" != -* || "$prev" == -* ]]; then
         local IFS=$'\n'
         COMPREPLY=( $( compgen -g "$cur" 2>/dev/null ) )
     else
@@ -935,7 +934,7 @@ _mount()
 
     for i in {,/usr}/{,s}bin/showmount; do [ -x $i ] && sm=$i && break; done
 
-    if [ -n "$sm" ] && [[ "$cur" == *:* ]]; then
+    if [[ -n "$sm" && "$cur" == *:* ]]; then
         COMPREPLY=( $( compgen -W "$( $sm -e ${cur%%:*} | sed 1d | \
             awk '{print $1}' )" -- "$cur" ) )
     elif [[ "$cur" == //* ]]; then
@@ -1000,8 +999,7 @@ _insmod()
     prev=${COMP_WORDS[COMP_CWORD-1]}
 
     # behave like lsmod for modprobe -r
-    if [ ${1##*/} = "modprobe" ] &&
-        [ "${COMP_WORDS[1]}" = "-r" ]; then
+    if [[ ${1##*/} == modprobe && "${COMP_WORDS[1]}" == -r ]]; then
         _installed_modules "$cur"
         return 0
     fi
@@ -1012,8 +1010,7 @@ _insmod()
         return 0
     fi
 
-    if [ $COMP_CWORD -gt 1 ] &&
-        [[ "${COMP_WORDS[COMP_CWORD-1]}" != -* ]]; then
+    if [[ $COMP_CWORD -gt 1 && "${COMP_WORDS[COMP_CWORD-1]}" != -* ]]; then
         # do module parameter completion
         COMPREPLY=( $( compgen -W "$( /sbin/modinfo -p ${COMP_WORDS[1]} | \
             cut -d: -f1 )" -- "$cur" ) )
@@ -1039,7 +1036,7 @@ _renice()
 
     i=0
     # walk back through command line and find last option
-    while [ $i -le $COMP_CWORD -a ${#COMPREPLY[@]} -eq 0 ]; do
+    while [[ $i -le $COMP_CWORD && ${#COMPREPLY[@]} -eq 0 ]]; do
         curopt=${COMP_WORDS[COMP_CWORD-$i]}
         case "$curopt" in
             -u)
@@ -1067,7 +1064,7 @@ _kill()
     COMPREPLY=()
     cur=`_get_cword`
 
-    if [ $COMP_CWORD -eq 1 ] && [[ "$cur" == -* ]]; then
+    if [[ $COMP_CWORD -eq 1 && "$cur" == -* ]]; then
         # return list of available signals
         _signals
     else
@@ -1079,7 +1076,7 @@ complete -F _kill kill
 
 # killall(1) (Linux and FreeBSD) and pkill(1) completion.
 #
-[ $UNAME = Linux -o $UNAME = FreeBSD ] || have pkill &&
+[[ $UNAME == Linux || $UNAME == FreeBSD ]] || have pkill &&
 _killall()
 {
     local cur
@@ -1087,7 +1084,7 @@ _killall()
     COMPREPLY=()
     cur=`_get_cword`
 
-    if [ $COMP_CWORD -eq 1 ] && [[ "$cur" == -* ]]; then
+    if [[ $COMP_CWORD -eq 1 && "$cur" == -* ]]; then
         _signals
     else
         _pnames
@@ -1095,7 +1092,7 @@ _killall()
 
     return 0
 }
-[ $UNAME = Linux -o $UNAME = FreeBSD ] && complete -F _killall killall
+[[ $UNAME == Linux || $UNAME == FreeBSD ]] && complete -F _killall killall
 have pkill && complete -F _killall pkill
 
 # pgrep(1) completion.
@@ -1208,8 +1205,8 @@ _known_hosts()
 
     # NOTE: Using `_known_hosts' as a helper function and passing options
     #       to `_known_hosts' is deprecated: Use `_known_hosts_real' instead.
-    [ "$1" = -a ] || [ "$2" = -a ] && options=-a
-    [ "$1" = -c ] || [ "$2" = -c ] && options="$options -c"
+    [[ "$1" == -a || "$2" == -a ]] && options=-a
+    [[ "$1" == -c || "$2" == -c ]] && options="$options -c"
     _known_hosts_real $options "$(_get_cword :)"
 } # _known_hosts()
 
@@ -1303,7 +1300,7 @@ _known_hosts_real()
     fi
 
     # If we have known_hosts files to use
-    if [ ${#kh[@]} -gt 0 -o ${#khd[@]} -gt 0 -o -n "$configfile" ]; then
+    if [[ ${#kh[@]} -gt 0 || ${#khd[@]} -gt 0 || -n "$configfile" ]]; then
         # Escape slashes and dots in paths for awk
         awkcur=${cur//\//\\\/}
         awkcur=${awkcur//\./\\\.}
@@ -1339,7 +1336,7 @@ _known_hosts_real()
             # dont fork any processes, because in a cluster environment,
             # there can be hundreds of hostkeys
             for i in "${khd[@]}" ; do
-                if [[ "$i" == *key_22_$awkcurd*.pub ]] && [ -r "$i" ] ; then
+                if [[ "$i" == *key_22_$awkcurd*.pub && -r "$i" ]]; then
                     host=${i/#*key_22_/}
                     host=${host/%.pub/}
                     COMPREPLY=( "${COMPREPLY[@]}" $host )
@@ -1347,7 +1344,7 @@ _known_hosts_real()
             done
         fi
         # append any available aliases from config files
-        if [ ${#config[@]} -gt 0 ] && [ -n "$aliases" ]; then
+        if [[ ${#config[@]} -gt 0 && -n "$aliases" ]]; then
             local host_aliases=$( sed -ne 's/^[ \t]*[Hh][Oo][Ss][Tt]\([Nn][Aa][Mm][Ee]\)\?['"$'\t '"']\{1,\}\([^#*?]*\)\(#.*\)\?$/\2/p' "${config[@]}" )
             hosts=$( compgen -W "$host_aliases" -- "$cur" )
             COMPREPLY=( "${COMPREPLY[@]}" $hosts )
@@ -1404,7 +1401,7 @@ _cd()
 
     # Use standard dir completion if no CDPATH or parameter starts with /,
     # ./ or ../
-    if [ -z "${CDPATH:-}" ] || [[ "$cur" == ?(.)?(.)/* ]]; then
+    if [[ -z "${CDPATH:-}" || "$cur" == ?(.)?(.)/* ]]; then
         _filedir -d
         return 0
     fi
@@ -1428,7 +1425,7 @@ _cd()
 
     if [[ ${#COMPREPLY[@]} -eq 1 ]]; then
         i=${COMPREPLY[0]}
-        if [ "$i" == "$cur" ] && [[ $i != "*/" ]]; then
+        if [[ "$i" == "$cur" && $i != "*/" ]]; then
             COMPREPLY[0]="${i}/"
         fi
     fi
@@ -1687,27 +1684,27 @@ fi
 unset list
 
 # source completion directory definitions
-if [ -d $BASH_COMPLETION_COMPAT_DIR -a -r $BASH_COMPLETION_COMPAT_DIR -a \
-    -x $BASH_COMPLETION_COMPAT_DIR ]; then
+if [[ -d $BASH_COMPLETION_COMPAT_DIR && -r $BASH_COMPLETION_COMPAT_DIR && \
+    -x $BASH_COMPLETION_COMPAT_DIR ]]; then
     for i in $(LC_ALL=C command ls $BASH_COMPLETION_COMPAT_DIR); do
         i=$BASH_COMPLETION_COMPAT_DIR/$i
-        [[ ${i##*/} != @(*~|*.bak|*.swp|\#*\#|*.dpkg*|*.rpm@(orig|new|save)) ]] &&
-        [ \( -f $i -o -h $i \) -a -r $i ] && . $i
+        [[ ${i##*/} != @(*~|*.bak|*.swp|\#*\#|*.dpkg*|*.rpm@(orig|new|save)) \
+            && ( -f $i || -h $i ) && -r $i ]] && . $i
     done
 fi
-if [ -d $BASH_COMPLETION_DIR -a -r $BASH_COMPLETION_DIR -a \
-    $BASH_COMPLETION_DIR != $BASH_COMPLETION_COMPAT_DIR -a \
-    -x $BASH_COMPLETION_DIR ]; then
+if [[ $BASH_COMPLETION_DIR != $BASH_COMPLETION_COMPAT_DIR && \
+    -d $BASH_COMPLETION_DIR && -r $BASH_COMPLETION_DIR && \
+    -x $BASH_COMPLETION_DIR ]]; then
     for i in $(LC_ALL=C command ls $BASH_COMPLETION_DIR); do
         i=$BASH_COMPLETION_DIR/$i
-        [[ ${i##*/} != @(*~|*.bak|*.swp|\#*\#|*.dpkg*|*.rpm@(orig|new|save)) ]] &&
-        [ \( -f $i -o -h $i \) -a -r $i ] && . $i
+        [[ ${i##*/} != @(*~|*.bak|*.swp|\#*\#|*.dpkg*|*.rpm@(orig|new|save)) \
+            && ( -f $i || -h $i ) && -r $i ]] && . $i
     done
 fi
 unset i
 
 # source user completion file
-[ $BASH_COMPLETION != ~/.bash_completion -a -r ~/.bash_completion ] \
+[[ $BASH_COMPLETION != ~/.bash_completion && -r ~/.bash_completion ]] \
     && . ~/.bash_completion
 unset -f have
 unset UNAME USERLAND have
diff --git a/contrib/abook b/contrib/abook
index fba0f240..b1b7b1f6 100644
--- a/contrib/abook
+++ b/contrib/abook
@@ -11,7 +11,7 @@ _abook()
 
     # abook only takes options, tabbing after command name adds a single
     # dash (bash4)
-    [ ${BASH_VERSINFO[0]} -ge 4 -a $COMP_CWORD -eq 1 -a -z "$cur" ] &&
+    [[ ${BASH_VERSINFO[0]} -ge 4 && $COMP_CWORD -eq 1 && -z "$cur" ]] &&
     {
         compopt -o nospace
         COMPREPLY=( "-" )
diff --git a/contrib/chkconfig b/contrib/chkconfig
index 864f8d85..a7eeb5f6 100644
--- a/contrib/chkconfig
+++ b/contrib/chkconfig
@@ -27,7 +27,7 @@ _chkconfig()
     if [[ "$cur" == -* ]]; then
         COMPREPLY=( $( compgen -W '--list --add --del --override --level' -- "$cur" ) )
     else
-        if [ $COMP_CWORD -eq 2 -o $COMP_CWORD -eq 4 ]; then
+        if [[ $COMP_CWORD -eq 2 || $COMP_CWORD -eq 4 ]]; then
             COMPREPLY=( $( compgen -W 'on off reset resetpriorities' -- "$cur" ) )
         else
             _services
diff --git a/contrib/cpan2dist b/contrib/cpan2dist
index 86172204..f6974d40 100644
--- a/contrib/cpan2dist
+++ b/contrib/cpan2dist
@@ -34,7 +34,7 @@ _cpan2dist()
     else
         cpandirs=( "$HOME/.cpanplus/" "$HOME/.cpan/source/modules/" )
         for dir in ${cpandirs[@]}; do
-            [ -d "$dir" -a -r "$dir/02packages.details.txt.gz" ] && \
+            [[ -d "$dir" && -r "$dir/02packages.details.txt.gz" ]] && \
                 packagelist="$dir/02packages.details.txt.gz"
         done
         COMPREPLY=( $( zgrep "^${cur//-/::}" \
diff --git a/contrib/cvs b/contrib/cvs
index 68b138aa..0c694c7d 100644
--- a/contrib/cvs
+++ b/contrib/cvs
@@ -56,7 +56,7 @@ _cvs()
     for i in "${COMP_WORDS[@]}"; do
         [ $count -eq $COMP_CWORD ] && break
         # Last parameter was the CVSROOT, now go back to mode selection
-        if [ "${COMP_WORDS[((count))]}" == "$cvsroot" -a "$mode" == "cvsroot" ]; then
+        if [[ "${COMP_WORDS[((count))]}" == "$cvsroot" && "$mode" == cvsroot ]]; then
             mode=""
         fi
         if [ -z "$mode" ]; then
@@ -144,7 +144,7 @@ _cvs()
 
             if [[ "$cur" != -* ]]; then
                 set_prefix
-                if [ $COMP_CWORD -gt 1 -a -r ${prefix:-}CVS/Entries ]; then
+                if [[ $COMP_CWORD -gt 1 && -r ${prefix:-}CVS/Entries ]]; then
                     get_entries
                     [ -z "$cur" ] && \
                     files=$( command ls -Ad !(CVS) ) || \
@@ -293,7 +293,7 @@ _cvs()
         remove)
             if [[ "$cur" != -* ]]; then
                 set_prefix
-                if [ $COMP_CWORD -gt 1 -a -r ${prefix:-}CVS/Entries ]; then
+                if [[ $COMP_CWORD -gt 1 && -r ${prefix:-}CVS/Entries ]]; then
                     get_entries
                     # find out what files are missing
                     for i in "${entries[@]}"; do
diff --git a/contrib/dpkg b/contrib/dpkg
index ea7ee306..4cacd4ee 100644
--- a/contrib/dpkg
+++ b/contrib/dpkg
@@ -167,7 +167,7 @@ _dpkg_source()
     done
     case "$action" in
         "unpack")
-            if [ "$cur" = "-" -o "$cur" = "-s" ]; then
+            if [[ "$cur" == - || "$cur" == -s ]]; then
                 COMPREPLY=( $unpackopts )
                 return 0
             fi
diff --git a/contrib/findutils b/contrib/findutils
index 0d0684f5..09d2f447 100644
--- a/contrib/findutils
+++ b/contrib/findutils
@@ -70,7 +70,7 @@ _find()
     done
 
     # handle case where first parameter is not a dash option
-    if [ "$exprfound" != 1 ] && [[ "$cur" != [-\(\),\!]* ]]; then
+    if [[ "$exprfound" != 1 && "$cur" != [-\(\),\!]* ]]; then
         _filedir -d
         return 0
     fi
@@ -94,8 +94,7 @@ _find()
        -noleaf -version -xdev '
     COMPREPLY=( $( echo "${COMP_WORDS[@]}" | \
            (while read -d ' ' i; do
-            [ "$i" == "" ] ||
-            [ "${onlyonce/ ${i%% *} / }" == "$onlyonce" ] &&
+            [[ -z "$i" || "${onlyonce/ ${i%% *} / }" == "$onlyonce" ]] &&
             continue
             # flatten array with spaces on either side,
             # otherwise we cannot grep on word boundaries of
diff --git a/contrib/gzip b/contrib/gzip
index 00dd4a5f..48f97011 100644
--- a/contrib/gzip
+++ b/contrib/gzip
@@ -26,7 +26,7 @@ _gzip()
     elif [[ "$prev" == -* ]]; then
         [[ "$prev" == -*[dlt]* ]] && xspec="!"$xspec
         [[ "$prev" == -*f* ]] && xspec=
-    elif [ "$prev" = '>' -o "$prev" = '>>' ]; then
+    elif [[ "$prev" == '>' || "$prev" == '>>' ]]; then
         xspec=
     elif [ "$prev" = '<' ]; then
         xspec=
diff --git a/contrib/iptables b/contrib/iptables
index 25ab35a7..5e07efac 100644
--- a/contrib/iptables
+++ b/contrib/iptables
@@ -29,7 +29,7 @@ _iptables()
         COMPREPLY=( $( compgen -W 'nat filter mangle' -- "$cur" ) )
         ;;
     -j)
-        if [ "$table" = "-t filter" -o "$table" = "" ]; then
+        if [[ "$table" == "-t filter" || -z "$table" ]]; then
             COMPREPLY=( $( compgen -W 'ACCEPT DROP LOG ULOG REJECT \
                 `iptables $table -nL | sed -ne "$chain" \
                 -e "s/INPUT|OUTPUT|FORWARD|PREROUTING|POSTROUTING//"`' -- \
diff --git a/contrib/java b/contrib/java
index d23a5ca1..70f98d46 100644
--- a/contrib/java
+++ b/contrib/java
@@ -60,7 +60,7 @@ _java_classes()
     cur=${cur//.//}
     # parse each classpath element for classes
     for i in ${classpath//:/ }; do
-        if [ -r $i ] && [[ "$i" == *.@(jar|zip) ]]; then
+        if [[ -r $i && "$i" == *.@(jar|zip) ]]; then
             if type zipinfo &>/dev/null; then
                 COMPREPLY=( "${COMPREPLY[@]}" $( zipinfo -1 \
                     "$i" "$cur*" 2>/dev/null | \
diff --git a/contrib/larch b/contrib/larch
index 3a559332..6dcaf545 100644
--- a/contrib/larch
+++ b/contrib/larch
@@ -9,7 +9,7 @@ _larch()
     cur=`_get_cword`
     prev=${COMP_WORDS[COMP_CWORD-1]}
 
-    if [ $COMP_CWORD -eq 1 ] || [[ "$prev" == -* ]]; then
+    if [[ $COMP_CWORD -eq 1 || "$prev" == -* ]]; then
         COMPREPLY=( $( compgen -W ' \
             my-id my-default-archive register-archive whereis-archive archives \
             init-tree tree-root tree-version set-tree-version inventory \
diff --git a/contrib/lvm b/contrib/lvm
index b8e21afb..d8b0122d 100644
--- a/contrib/lvm
+++ b/contrib/lvm
@@ -656,7 +656,7 @@ _vgsplit()
             --verbose --version' -- "$cur" ) )
     else
         _args
-        if [ $args -eq 0 -o $args -eq 1 ]; then
+        if [[ $args -eq 0 || $args -eq 1 ]]; then
             _volumegroups
         else
             _physicalvolumes
diff --git a/contrib/mplayer b/contrib/mplayer
index 0e3838a8..7a43f84e 100644
--- a/contrib/mplayer
+++ b/contrib/mplayer
@@ -39,7 +39,7 @@ _mplayer()
             _filedir '@(idx|IDX|ifo|IFO|sub|SUB)'
             IFS=$'\t\n'
             COMPREPLY=( $( for i in "${COMPREPLY[@]}"; do
-                        if [ -f $i -a -r $i ]; then
+                        if [[ -f $i && -r $i ]]; then
                             echo ${i%.*}
                         else
                             echo $i
@@ -67,7 +67,7 @@ _mplayer()
 
             IFS=$'\t\n'
             for i in ~/.mplayer/Skin $skinsdir; do
-                if [ -d $i -a -r $i ]; then
+                if [[ -d $i && -r $i ]]; then
                     for j in $( compgen -d $i/$cur ); do
                         COMPREPLY[$k]=${j#$i/}
                         k=$((++k))
diff --git a/contrib/mutt b/contrib/mutt
index d0d13eba..452f79cf 100644
--- a/contrib/mutt
+++ b/contrib/mutt
@@ -94,7 +94,7 @@ _muttquery()
     local -a queryresults
 
     querycmd="$( $muttcmd -Q query_command  | sed -r 's|^query_command=\"(.*)\"$|\1|; s|%s|'$cur'|' )"
-    if [ -z "$cur" -o -z "$querycmd" ]; then
+    if [[ -z "$cur" || -z "$querycmd" ]]; then
         queryresults=()
     else
         queryresults=( $( $querycmd | sed -nr '2,$s|^([^[:space:]]+).*|\1|p' ) )
diff --git a/contrib/ncftp b/contrib/ncftp
index adb88a44..ba003aaf 100644
--- a/contrib/ncftp
+++ b/contrib/ncftp
@@ -8,7 +8,7 @@ _ncftp()
     COMPREPLY=()
     cur=`_get_cword`
 
-    if [ $COMP_CWORD -eq 1 ] && [ -f ~/.ncftp/bookmarks ]; then
+    if [[ $COMP_CWORD -eq 1 && -f ~/.ncftp/bookmarks ]]; then
         COMPREPLY=( $( compgen -W '$( sed -ne "s/^\([^,]\{1,\}\),.*$/\1/p" \
             ~/.ncftp/bookmarks )' -- "$cur" ) )
     fi
diff --git a/contrib/pkg_install b/contrib/pkg_install
index 443a9ac1..562596cd 100644
--- a/contrib/pkg_install
+++ b/contrib/pkg_install
@@ -11,7 +11,7 @@ _pkg_delete()
     cur=`_get_cword`
     prev=${COMP_WORDS[COMP_CWORD-1]}
 
-    [ "$prev" = "-o" -o "$prev" = "-p" -o "$prev" = "-W" ] && return 0
+    [[ "$prev" == -o || "$prev" == -p || "$prev" == -W ]] && return 0
 
     COMPREPLY=( $( compgen -d "$pkgdir$cur" ) )
     COMPREPLY=( ${COMPREPLY[@]#$pkgdir} )
diff --git a/contrib/portupgrade b/contrib/portupgrade
index cc051b17..65fa21ba 100644
--- a/contrib/portupgrade
+++ b/contrib/portupgrade
@@ -9,7 +9,7 @@ _portupgrade()
     cur=`_get_cword`
     prev=${COMP_WORDS[COMP_CWORD-1]}
 
-    [ "$prev" = "-l" -o "$prev" = "-L" -o "$prev" = "-o" ] && return 0
+    [[ "$prev" == -l || "$prev" == -L || "$prev" == -o ]] && return 0
 
     COMPREPLY=( $( compgen -d "$pkgdir$cur" ) )
     COMPREPLY=( ${COMPREPLY[@]#$pkgdir} )
@@ -31,10 +31,10 @@ _portinstall()
     # First try INDEX-5
     indexfile=$portsdir/INDEX-5
     # Then INDEX if INDEX-5 does not exist or system is not FreeBSD 5.x
-    [ "${OSTYPE%.*}" = "freebsd5" -a -f $indexfile ] ||
-      indexfile=$portsdir/INDEX
+    [[ "${OSTYPE%.*}" == freebsd5 && -f $indexfile ]] ||
+        indexfile=$portsdir/INDEX
 
-    [ "$prev" = "-l" -o "$prev" = "-L" -o "$prev" = "-o" ] && return 0
+    [[ "$prev" == -l || "$prev" == -L || "$prev" == -o ]] && return 0
 
     COMPREPLY=( $( egrep "^$cur" < $indexfile | cut -d'|' -f1 ) )
     COMPREPLY2=( $( egrep "^[^\|]+\|$portsdir$cur" < $indexfile | \
diff --git a/contrib/rcs b/contrib/rcs
index 0fb3fecb..36ebaa5a 100644
--- a/contrib/rcs
+++ b/contrib/rcs
@@ -31,7 +31,7 @@ _rcs()
 
     # default to files if nothing returned and we're checking in.
     # otherwise, default to directories
-    [ ${#COMPREPLY[@]} -eq 0 -a $1 = ci ] && _filedir || _filedir -d
+    [[ ${#COMPREPLY[@]} -eq 0 && $1 == ci ]] && _filedir || _filedir -d
 } &&
 complete -F _rcs -o filenames ci co rlog rcs rcsdiff
 
diff --git a/contrib/rfkill b/contrib/rfkill
index df3dde69..ec331e0d 100644
--- a/contrib/rfkill
+++ b/contrib/rfkill
@@ -18,7 +18,7 @@ _rfkill()
                 ;;
             2)
                 prev=${COMP_WORDS[COMP_CWORD-1]}
-                if [ $prev == block -o $prev == unblock ]; then
+                if [[ $prev == block || $prev == unblock ]]; then
                     COMPREPLY=( $( compgen -W "$(rfkill list | awk -F: \
                         '/^[0-9]/ {print $1}') all wifi bluetooth uwb wimax \
                         wwan gps" -- "$cur" ) )
diff --git a/contrib/rpm b/contrib/rpm
index e760f277..e21ea48f 100644
--- a/contrib/rpm
+++ b/contrib/rpm
@@ -7,8 +7,8 @@ _rpm_installed_packages()
 {
     local nodig="$1" nosig="$2"
 
-    if [ -r /var/log/rpmpkgs -a \
-        /var/log/rpmpkgs -nt /var/lib/rpm/Packages ]; then
+    if [[ -r /var/log/rpmpkgs && \
+        /var/log/rpmpkgs -nt /var/lib/rpm/Packages ]]; then
         # using RHL 7.2 or later - this is quicker than querying the DB
         COMPREPLY=( $( sed -ne \
             's|^\('$cur'[^[:space:]]*\)-[^[:space:]-]\{1,\}-[^[:space:]-]\{1,\}\.rpm$|\1|p' \
@@ -33,7 +33,7 @@ _rpm_groups()
 
 _rpm_nodigsig()
 {
-    if [ -z "$nodig" -a -z "$nosig" ]; then
+    if [[ -z "$nodig" && -z "$nosig" ]]; then
         local rpmver
 
         rpmver=$(rpm --version)
diff --git a/contrib/yp-tools b/contrib/yp-tools
index 60155279..0da14ad9 100644
--- a/contrib/yp-tools
+++ b/contrib/yp-tools
@@ -8,16 +8,15 @@ _ypmatch()
     COMPREPLY=()
     cur=`_get_cword`
 
-    [ $1 = ypcat ] && [ $COMP_CWORD -gt 1 ] && return 0
-    [ $1 = ypmatch ] && [ $COMP_CWORD -gt 2 ] && return 0
+    [[ $1 == ypcat && $COMP_CWORD -gt 1 ]] && return 0
+    [[ $1 == ypmatch && $COMP_CWORD -gt 2 ]] && return 0
 
-    if [ $1 = ypmatch ] && [ $COMP_CWORD -eq 1 ] && \
-       [ ${#COMP_WORDS[@]} -eq 3 ]; then
+    if [[ $1 == ypmatch && $COMP_CWORD -eq 1 && ${#COMP_WORDS[@]} -eq 3 ]]; then
         map=${COMP_WORDS[2]}
         COMPREPLY=( $( compgen -W '$( ypcat $map | \
             cut -d':' -f 1 )' -- "$cur") )
     else
-        [ $1 = ypmatch ] && [ $COMP_CWORD -ne 2 ] && return 0
+        [[ $1 == ypmatch && $COMP_CWORD -ne 2 ]] && return 0
         COMPREPLY=( $( compgen -W \
             '$( echo $(ypcat -x | cut -d"\"" -f 2))' -- "$cur"))
     fi