fix: avoid echo usage

Echo can interpret operand as an option and checking every variable to
be echoed is troublesome while with printf, if the format specifier is
present before the operand, printing as string can be enforced.

files/dom0/.local/bin/dom0/qvm-restart

@@ -6,7 +6,8 @@
 
 set -eu
 
-test -n "${1:-}" || { echo "Usage: ${0##*/} QUBE [QUBE ...]"; exit 1; }
+test -n "${1:-}" ||
+  { printf '%s\n' "Usage: ${0##*/} QUBE [QUBE ...]"; exit 1; }
 
 vms="${*}"
 

files/dom0/.local/bin/dom0/qvm-stats

@@ -10,11 +10,11 @@
 set -eu
 
 if ! command -v sensors >/dev/null; then
-  echo "Program not installed: sensors" >&2
+  printf '%s\n' "Program not installed: sensors" >&2
   exit 1
 fi
 if ! command -v xentop >/dev/null; then
-  echo "Program not installed: xentop" >&2
+  printf '%s\n' "Program not installed: xentop" >&2
   exit 1
 fi
 

files/dom0/.local/share/bash-completion/completions/qvm

@@ -24,7 +24,7 @@ _get-cword-pos() {
     [[ ${COMP_WORDS[i]} == -* ]] && continue
     ((index++))
   done
-  echo ${index}
+  printf '%s\n' "${index}"
 }
 
 # Get the relative position of the first COMP_CWORD with option words ignored
@@ -33,10 +33,10 @@ _get-first-cword() {
   local i
   for ((i=1; i<=COMP_CWORD; i++)); do
     [[ ${COMP_WORDS[i]} == -* ]] && continue
-    echo "${COMP_WORDS[i]}"
+    printf '%s\n' "${COMP_WORDS[i]}"
     return 0
   done
-  echo ""
+  printf '%s\n' ""
 }
 
 

files/git/.config/git/config

@@ -71,16 +71,16 @@
 	add-unmerged = "!f() { git diff --name-status --diff-filter=U | cut -f2 ; }; git add $(f)"
 	; List tips of branches that are not in the first arg.
 	; git tips origin/master ^origin/alternate | git oneline
-	oneline ="!_() { $(test $# -eq 0 && echo xargs -L1) git log --no-walk --decorate --oneline \"$@\"; }; _"
-	tips = "!_() { t=$(git rev-list --no-merges --max-count=1 \"$@\"); if test -n \"$t\"; then echo $t; _ \"$@\" ^$t; fi; }; _"
+	oneline ="!_() { $(test $# -eq 0 && printf '%s\n' \"xargs -L1\") git log --no-walk --decorate --oneline \"$@\"; }; _"
+	tips = "!_() { t=$(git rev-list --no-merges --max-count=1 \"$@\"); if test -n \"$t\"; then printf '%s\n' \"$t\"; _ \"$@\" ^$t; fi; }; _"
 	; Submodules.
 	sub-update = !sh -c 'git checkout $1 && git submodule update --recursive'
 	; Signed tags and commits
 	stag = "!sh -c 'commit_id=\"$(git rev-parse --verify \"$@\")\"; \
-		tag_name=\"signed_tag_for_$(echo $commit_id | cut -c 1-8)\"; \
+		tag_name=\"signed_tag_for_$(printf '%s\n' \"$commit_id\" | cut -c 1-8)\"; \
 		git tag -s \"$tag_name\" \
 			-m \"Tag for commit $commit_id\" \"$commit_id\"; \
-		echo \"$tag_name\"'" -
+		printf '%s\n' \"$tag_name\"'" -
 	ptag = !git push $(git config branch.$(git branch --show-current).remote) $(git describe)
 	vtag = !git verify-tag -v $(git describe)
 	vhci = !git verify-commit -v $(git rev-parse HEAD)

files/git/.config/git/shell/.git-shell-lib

@@ -18,14 +18,14 @@ regex="^[A-Za-z0-9]+([A-Za-z0-9_.-]+[A-Za-z0-9]+)?$"
 description_regex="^[A-Za-z0-9 _.-]+$"
 
 fail_invalid_name(){
-  echo "Error: invalid value for key: $1" >&2
+  printf '%s\n' "Error: invalid value for key: $1" >&2
   exit 1
 }
 
 test_description(){
   key="$1"
   value="$2"
-  if ! (echo "${value}" | grep -E -q -e "${description_regex}"); then
+  if ! (printf '%s\n' "${value}" | grep -E -q -e "${description_regex}"); then
     fail_invalid_name "${key}"
   fi
 }
@@ -33,7 +33,7 @@ test_description(){
 test_name(){
   key="$1"
   value="$2"
-  if ! (echo "${value}" | grep -E -q -e "${regex}"); then
+  if ! (printf '%s\n' "${value}" | grep -E -q -e "${regex}"); then
     fail_invalid_name "${key}"
   fi
 }
@@ -48,12 +48,12 @@ clean_repo_name(){
 is_bare(){
   _repo="$1"
   if ! test -d "${_repo}"; then
-    echo "Repository doesn't exist: ${_repo}" >&2
+    printf '%s\n' "Repository doesn't exist: ${_repo}" >&2
     return 1
   fi
   bare_repo_check="$(git -C "${_repo}" rev-parse --is-bare-repository)"
   if ! test "${bare_repo_check}" = "true"; then
-    echo "Repository is not bare: ${_repo}" >&2
+    printf '%s\n' "Repository is not bare: ${_repo}" >&2
     return 1
   fi
 }

files/git/.config/git/shell/.no-interactive-login.sample

@@ -6,7 +6,7 @@
 
 set -eu
 
-echo "Hello there. You've successfully authenticated, but interactive
+printf '%s\n' "Hello there. You've successfully authenticated, but interactive
 shell access is not available. You have access to these repositories:" >&2
 "${0%/*}"/list >&2
 

files/git/.config/git/shell/description

@@ -11,7 +11,7 @@ set -eu
 
 usage(){
   # shellcheck disable=2154
-  echo "usage: ${0##*/} SECTION REPOSITORY [DESCRIPTION]
+  printf '%s\n' "usage: ${0##*/} SECTION REPOSITORY [DESCRIPTION]
 note: prints the current description if none description is specified.:w
 regex: ${regex}" >&2
   exit 1
@@ -35,7 +35,7 @@ if test -z "${3-}"; then
   exit 0
 fi
 
-description="$(echo "$3" | cut -c 1-80)"
+description="$(printf '%s\n' "$3" | cut -c 1-80)"
 test_description description "${description}"
 
-echo "${description}" | tee "${description_file}"
+printf '%s\n' "${description}" | tee "${description_file}"

files/git/.config/git/shell/init

@@ -11,7 +11,7 @@ set -eu
 
 usage(){
   # shellcheck disable=2154
-  echo "usage: ${0##*/} SECTION REPOSITORY [BRANCH]
+  printf '%s\n' "usage: ${0##*/} SECTION REPOSITORY [BRANCH]
 regex: ${regex}" >&2
   exit 1
 }

files/git/.config/git/shell/list

@@ -14,7 +14,7 @@ set -eu
 
 usage(){
   # shellcheck disable=2154
-  echo "usage: ${0##*/} [SECTION]
+  printf '%s\n' "usage: ${0##*/} [SECTION]
 regex: ${regex}" >&2
   exit 1
 }
@@ -28,7 +28,7 @@ esac
 
 # shellcheck disable=SC2154
 if ! test -d "${base}/${section}"; then
-  echo "Section doesn't exist: ${section}" >&2
+  printf '%s\n' "Section doesn't exist: ${section}" >&2
   exit 1
 fi
 

files/git/.config/git/template/hooks/pre-receive.sample

@@ -41,7 +41,7 @@ tmpdir="$(mktemp -d "${TMPDIR:-/tmp}/XXXXXX")"
 trap 'rm -f "${tmpdir}"' HUP INT QUIT ABRT TERM EXIT
 
 err(){
-  echo "${*}" >&2
+  printf '%s\n' "${*}" >&2
 }
 
 require_signed_push(){
@@ -78,7 +78,7 @@ check_signed_push(){
 check_signed_push_keyring(){
   true "Using keyring to verify push certificate: ${GIT_PUSH_CERT_PGPHOMEDIR}"
 
-  gpg="$(git config --get gpg.program || echo "gpg")"
+  gpg="$(git config --get gpg.program || printf '%s\n' "gpg")"
   cert="$(git cat-file blob "${GIT_PUSH_CERT}")"
   begin_sig="-----BEGIN PGP SIGNATURE-----"
 
@@ -86,12 +86,12 @@ check_signed_push_keyring(){
   cert_sig="${tmpdir}"/cert.sig
 
   in_sig=0
-  echo "${cert}" | while read -r line; do
+  printf '%s\n' "${cert}" | while read -r line; do
     if test "${in_sig}" = "1" || test "${line}" = "${begin_sig}"; then
       in_sig=1
-      echo "${line}" | tee -a "${cert_sig}"
+      printf '%s\n' "${line}" | tee -a "${cert_sig}"
     elif test "${line}" != "${begin_sig}"; then
-      echo "${line}" | tee -a "${cert_msg}"
+      printf '%s\n' "${line}" | tee -a "${cert_msg}"
     else
       break
     fi
@@ -101,7 +101,7 @@ check_signed_push_keyring(){
               --homedir "${GIT_PUSH_CERT_PGPHOMEDIR}" \
               --verify "${cert_sig}" "${cert_msg}" 2>&1)"
   gpg_ec="$?"
-  gpg_sig="$(echo "${gpg_out}" | awk '/ GOODSIG /{print $3}')"
+  gpg_sig="$(printf '%s\n' "${gpg_out}" | awk '/ GOODSIG /{print $3}')"
   if test "${gpg_ec}" = "0"; then
     true "Cert validation succeeded. Key: ${gpg_sig}"
   else
@@ -142,7 +142,8 @@ while read -r oldrev newrev ref; do
       continue
     fi
     commit_tag="$(git rev-list -n1 "${newrev}")"
-    obj_rejected="$(echo "${obj_rejected}" | sed -e "s/ ${commit_tag} //")"
+    obj_rejected="$(printf '%s\n' "${obj_rejected}" | \
+      sed -e "s/ ${commit_tag} //")"
     err "Commit validation done by tag: ${commit_tag} ${newrev}"
     continue
   fi
@@ -162,7 +163,7 @@ done
 
 test -n "${obj_rejected}" || exit 0
 
-obj_rejected="$(echo "${obj_rejected}" | tr -s " " |
+obj_rejected="$(printf '%s\n' "${obj_rejected}" | tr -s " " |
   sed -e "s/^ //" -e "s/ $//")"
 err "Couldn't verify objects: ${obj_rejected}"
 exit 1
@@ -191,7 +192,8 @@ while read -r oldrev newrev ref; do
       continue
     fi
     commit_tag="$(git rev-list -n1 "${newrev}")"
-    obj_rejected="$(echo "${obj_rejected}" | sed -e "s/ ${commit_tag} //")"
+    obj_rejected="$(printf '%s\n' "${obj_rejected}" | \
+      sed -e "s/ ${commit_tag} //")"
     err "Commit validation done by tag: ${commit_tag} ${newrev}"
     continue
   fi
@@ -209,6 +211,7 @@ done
 
 test -n "${obj_rejected}" || exit 0
 
-obj_rejected="$(echo "${obj_rejected}" | tr -s " " | sed -e "s/^ //;s/ $//")"
+obj_rejected="$(printf '%s\n' "${obj_rejected}" | tr -s " " | \
+  sed -e "s/^ //;s/ $//")"
 err "Couldn't verify objects: ${obj_rejected}"
 exit 1

files/git/.config/git/template/hooks/prepare-commit-msg

@@ -14,7 +14,7 @@ file="$1"
 #commit_source="$2"
 #sha1="$3"
 
-char="$(git config --get core.commentChar || echo "#")"
+char="$(git config --get core.commentChar || printf '%s\n' "#")"
 template="$(git config --get commit.template | sed -e "s|^~/|${HOME}/|")"
 
 if test "${char}" = "auto"; then
@@ -34,7 +34,7 @@ sed -i'' \
 ## Replace init.template comment char to the core.commentChar line per line.
 if test -f "${template}"; then
   while read -r line; do
-    mod_line="$(echo "${line}" | sed -e "s/^. /${char} /")"
+    mod_line="$(printf '%s\n' "${line}" | sed -e "s/^. /${char} /")"
     sed -i'' -e "s/^${line}$/${mod_line}/" -- "${file}"
   done < "${template}"
 fi

files/git/.local/bin/git-server-setup

@@ -9,7 +9,7 @@ set -eu
 
 uid="$(id -u)"
 if ! test "${uid}" = "0"; then
-  echo "This program requires root." >&2
+  printf '%s\n' "This program requires root." >&2
   exit 1
 fi
 

files/mutt/.local/bin/mutt-sorcerer

@@ -17,18 +17,18 @@ local_file="${HOME}/.muttrc.local"
 source_existent(){
   for file in "${@}"; do
     if test -f "${file}"; then
-      echo source "\"${file}\""
+      printf '%s\n' "source \"${file}\""
     fi
   done
   unset file
 }
 
 ## Source files that must exist, let mutt fail otherwise.
-echo source "\"${credentials_file}\""
+printf '%s\n' "source \"${credentials_file}\""
 
 ## PWD is inherited from the muttrc that called this script.
 for file in *.muttrc; do
-  echo source "\"${file}\""
+  printf '%s\n' "source \"${file}\""
 done
 unset file
 

files/qvm-copy-dotfiles

@@ -14,16 +14,17 @@
 ## sudo ./qvm-copy-dotfiles QUBE
 set -eu
 
-test -n "${1:-}" || { echo "usage: ${0##*/} QUBE"; exit 1; }
+test -n "${1:-}" || { printf '%s\n' "usage: ${0##*/} QUBE"; exit 1; }
 uid="$(id -u)"
-test "${uid}" = "0" || { echo "Program requires root."; exit 1; }
+test "${uid}" = "0" || { printf '%s\n' "Program requires root."; exit 1; }
 
 qube="${1-}"
 if ! qvm-check -- "${qube}" >/dev/null 2>&1; then
-  echo "VM doesn't exist: '${qube}'"
+  printf '%s\n' "VM doesn't exist: '${qube}'"
   exit 1
 fi
-test -f ./setup.sh || { echo "File doesn't exist: './setup.sh'"; exit 1; }
+test -f ./setup.sh ||
+  { printf '%s\n' "File doesn't exist: './setup.sh'"; exit 1; }
 
 if test "${qube}" = "dom0"; then
   sh ./dotfiles/setup.sh

files/sh/.config/bash/bashrc

@@ -43,7 +43,7 @@ _reset_line() {
   esac
   ## Credit: Can't find the source, posted on StackExchange or alike.
   ## Does not work well on Bash 5.0 and older.
-  bash_version_clean="$(echo "${BASH_VERSION%.*}" | tr -d ".")"
+  bash_version_clean="$(printf '%s\n' "${BASH_VERSION%.*}" | tr -d ".")"
   if test "${bash_version_clean}" -lt 51; then
     unset bash_version_clean
     return

files/sh/.config/sh/profile

@@ -156,7 +156,7 @@ if test -z "${SSH_AUTH_SOCK-}" && has ssh-agent; then
     ssh_agent_env="$(ssh-agent -s -a "${ssh_agent_sock}")"
     eval "${ssh_agent_env}" >/dev/null
     unset ssh_agent_env
-    echo "${SSH_AGENT_PID}" | tee "${ssh_agent_pid}" >/dev/null
+    printf '%s\n' "${SSH_AGENT_PID}" | tee "${ssh_agent_pid}" >/dev/null
   fi
 fi
 unset ssh_agent_dir ssh_agent_sock ssh_agent_pid

files/sh/.config/sh/shrc

@@ -186,7 +186,7 @@ if test "${color_prompt-}" = "yes"; then
     ## Fix bold on some terminals.
     case "${TERM-}" in
       xterm*|screen*)
-        LS_COLORS="$(echo "${LS_COLORS}" | sed -e 's/01;3/00;9/g')"
+        LS_COLORS="$(printf '%s\n' "${LS_COLORS}" | sed -e 's/01;3/00;9/g')"
         ;;
       *) ;;
     esac

files/sh/.local/bin/has

@@ -20,7 +20,7 @@ action=""
 test -n "${1-}" || exit 1
 case "$1" in
   -s) action=show; shift; test -n "${1-}" || exit 1;;
-  "") echo "Argument required" >&2; exit 1;;
+  "") printf '%s\n' "Argument required" >&2; exit 1;;
   *) ;;
 esac
 

files/sh/.local/bin/resize-terminal

@@ -15,6 +15,8 @@ fi
 
 test -t 0 || exit 0
 
+msg_unsupported="error: cannot resize screen: unsupported terminal emulator"
+
 ## If argument is provided, allow user to bypass tty check.
 if test "${#}" -eq 0; then
   ## Shells on graphical sessions (terminal emulators) are skipped.
@@ -46,7 +48,7 @@ fi
 
 ## POSIX compliant.
 # shellcheck disable=SC3045
-if ! echo R | read -r -t 1 -sd R 2>/dev/null; then
+if ! printf '%s\n' "R" | read -r -t 1 -sd R 2>/dev/null; then
   ## Fast but depends on XTerm.
   if has resize; then
     resize_cmd="$(resize)"
@@ -68,7 +70,7 @@ stty -echo
 printf '\e7\e[r\033[99999;99999H\e[6n\e8' >/dev/tty
 # shellcheck disable=3045,SC2034
 IFS='[;R' read -r -t 1 -s -d R _ rows cols _ </dev/tty || {
-  echo "error: cannot resize screen: unsupported terminal emulator" >&2
+  printf '%s\n' "${msg_unsupported}" >&2
   stty echo
   unset rows cols
   exit 1
@@ -84,7 +86,7 @@ elif test "${rows}" -gt 0 && test "${cols}" -gt 0;then
   exit 0
 fi
 
-echo "error: cannot resize screen: unsupported terminal emulator" >&2
+printf '%s\n' "${msg_unsupported}" >&2
 stty echo
 unset rows cols
 exit 1

files/tmux/.local/bin/tmux-sorcerer

@@ -69,7 +69,7 @@ source_plugins(){
   do
     plugin_name="${plugin##*/}"
     plugin_name="${plugin_name##tmux-}"
-    plugin_name="$(echo "${plugin_name}" | tr "-" "_")"
+    plugin_name="$(printf '%s\n' "${plugin_name}" | tr "-" "_")"
     plugin_script="${plugin}/${plugin_name}.tmux"
     test -r "${plugin_script}" || continue
     "${plugin_script}" >/dev/null 2>&1