Shell New Added 8 September 2026

bash: $'\r': command not found

The script has Windows line endings. Bash treats the carriage return as part of the last token on each line, so commands, variables and the shebang all acquire an invisible character, producing errors that make no sense against the visible source.

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

Quick fix

# Confirm it
file deploy.sh          # "with CRLF line terminators"
cat -A deploy.sh | head # lines end with ^M$

# Convert
dos2unix deploy.sh
sed -i 's/\r$//' deploy.sh

# Stop git from reintroducing them
# .gitattributes
*.sh text eol=lf

git add --renormalize .

# Docker builds from a Windows checkout hit this constantly

How to diagnose Shell errors

Shell errors are usually about PATH, permissions, or quoting and expansion. The quoting class is the most damaging because it fails silently: an unquoted variable containing a space becomes two arguments, and an empty one disappears entirely. Running shellcheck over any script longer than a few lines catches most of these before they run.

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

Trace execution with bash -x script.sh to see each command after expansion. This makes quoting bugs immediately visible.
Start every script with set -euo pipefail so failures stop the script instead of cascading.
Quote every variable expansion: "$var", "${arr[@]}". This single habit prevents the majority of shell bugs.
Use command -v foo to check whether something is on PATH, and echo "$PATH" to see what the shell is actually searching.
In Makefiles, recipe lines must begin with a real tab character. "missing separator" always means spaces were used instead.

Tools worth reaching for

shellcheck
bash -x
set -euo pipefail
command -v
cat -A (to reveal tabs)

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

gnu.org

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This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.