Skip to content

Shell scripting glossary

Curated terms for the REBASH Shell Scripting course book.

  • array — Indexed or associative list of values in Bash (arr=(a b), ${arr[i]}).
  • Bash — Bourne Again SHell; the usual interactive and scripting shell on Linux.
  • builtin — Command implemented inside the shell (for example cd, read, printf).
  • cron — Time-based scheduler for recurring jobs.
  • exit status — Integer a process returns; 0 usually means success, non-zero means failure ($?).
  • function — Named block of shell code you can call with arguments (name() { … }).
  • glob — Filename pattern such as *.log expanded by the shell before a command runs.
  • here-document — Multi-line input redirected into a command (<<EOF … EOF).
  • IFS — Internal Field Separator; characters used to split words (often space/tab/newline).
  • jq — Command-line JSON processor used heavily in Cloud and DevOps scripts.
  • parameter expansion — ${var}, ${var:-default}, ${#var}, and related Bash forms.
  • pipe — Connects stdout of one command to stdin of the next (|).
  • POSIX sh — Portable shell dialect; stricter than Bash (often /bin/sh).
  • quoting — Rules that control expansion: single quotes literal, double quotes allow $ and backticks.
  • redirection — Send stdin/stdout/stderr to files or other descriptors (>, >>, 2>, &>).
  • set -euo pipefail — Common strict mode: exit on error, treat unset vars as errors, fail on pipe errors.
  • shebang — First line #!/usr/bin/env bash (or similar) that selects the interpreter.
  • signal — Kernel notification to a process (for example SIGINT, SIGTERM); handled with trap.
  • stderr — Standard error stream (file descriptor 2).
  • stdin — Standard input stream (file descriptor 0).
  • stdout — Standard output stream (file descriptor 1).
  • subshell — Child shell environment ( … ) or command substitution $(…).
  • systemd timer — Modern alternative to cron that activates a service unit on a schedule.
  • trap — Register commands to run when the shell receives a signal or exits.
  • variable — Named value in the shell (name=value, "$name").
  • yq — Command-line YAML processor (companion to jq for Kubernetes and config files).