Shell New Added 2 October 2026

bash: [: too many arguments

A variable inside single brackets was left unquoted and its value contained spaces, or a glob that matched several files. So [ was handed more words than it can parse. Because it depends on the data, the script works for months and then breaks the first time a filename or answer has a space in it.

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

# See exactly what [ receives
set -x

# Quote every expansion inside [ ]
if [ "$answer" = "yes" ]; then echo ok; fi

# Or use [[ ]] in bash, which does not split words
if [[ $answer == yes ]]; then echo ok; fi

# Testing for files from a glob: count them instead
shopt -s nullglob
files=(/var/log/app/*.log)
if (( ${#files[@]} > 0 )); then echo "found ${#files[@]}"; fi

# Catch these before they ship
shellcheck script.sh

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 shellcheck.net

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 If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.