{"id": "echo-basic", "cmd": "echo hello"}
{"id": "printf-args", "cmd": "printf '%s\\n' one two three"}
{"id": "pipe-sort", "cmd": "ls | sort"}
{"id": "grep-n", "cmd": "cat a.txt | grep -n line"}
{"id": "grep-count", "cmd": "grep -c ERROR logs/app.log"}
{"id": "redir-in", "cmd": "wc -l < a.txt"}
{"id": "redir-out-chain", "cmd": "head -2 data.csv > head.csv && cat head.csv"}
{"id": "csv-pipeline", "cmd": "tail -n +2 data.csv | cut -d, -f2 | sort | uniq -c | sort -rn"}
{"id": "arith", "cmd": "x=5; y=7; echo $((x*y+1))"}
{"id": "for-loop", "cmd": "for i in 1 2 3; do echo \"i=$i\"; done"}
{"id": "while-loop", "cmd": "i=0; while [ $i -lt 3 ]; do echo loop $i; i=$((i+1)); done"}
{"id": "until-loop", "cmd": "i=3; until [ $i -le 0 ]; do echo down $i; i=$((i-1)); done"}
{"id": "if-file", "cmd": "if [ -f a.txt ]; then echo yes; else echo no; fi"}
{"id": "case", "cmd": "case \"abc\" in a*) echo starts-a;; *) echo other;; esac"}
{"id": "func-basic", "cmd": "f() { echo \"fn:$1\"; }; f world"}
{"id": "func-local", "cmd": "greet() { local n=\"$1\"; echo \"hi $n\"; }; greet nash"}
{"id": "and-or", "cmd": "echo one && echo two || echo three"}
{"id": "or-fallback", "cmd": "false || echo fallback"}
{"id": "and-ok", "cmd": "true && echo ok"}
{"id": "subshell-cd", "cmd": "(cd src && pwd | xargs basename)"}
{"id": "param-default", "cmd": "VAR=hello; echo \"${VAR:-default} ${UNSET:-default}\""}
{"id": "param-strip", "cmd": "s=\"filename.tar.gz\"; echo \"${s%.gz} ${s%%.*} ${s#file}\""}
{"id": "param-replace-len", "cmd": "s=\"hello world\"; echo \"${s/world/nash} ${#s}\""}
{"id": "brace-expand", "cmd": "echo {a,b,c}{1,2}"}
{"id": "glob-txt", "cmd": "ls *.txt | sort"}
{"id": "array-basic", "cmd": "arr=(x y z); echo \"${arr[1]} ${#arr[@]} ${arr[@]}\""}
{"id": "awk-sum", "cmd": "seq 1 5 | awk '{s+=$1} END {print s}'"}
{"id": "sed-print", "cmd": "sed -n '2p' a.txt"}
{"id": "sed-file-out", "cmd": "sed 's/line/LINE/g' a.txt > upper.txt; wc -l upper.txt"}
{"id": "sort-uniq", "cmd": "sort b.txt | uniq | head -3"}
{"id": "cut-tr", "cmd": "cut -d, -f1 data.csv | tr 'a-z' 'A-Z' | tail -2"}
{"id": "find-name", "cmd": "find . -name '*.py' | sort"}
{"id": "find-exec", "cmd": "find src -type f -name '*.py' -exec wc -l {} + | sort -k2"}
{"id": "tr-wc", "cmd": "echo \"a b c\" | tr ' ' '\\n' | wc -l"}
{"id": "heredoc-expand", "cmd": "cat <<EOF\nheredoc line 1\nvalue: $((2+3))\nEOF"}
{"id": "heredoc-literal", "cmd": "cat <<'EOF'\nliteral $HOME\nEOF"}
{"id": "herestring-read", "cmd": "read first rest <<< \"alpha beta gamma\"; echo \"$first|$rest\""}
{"id": "append", "cmd": "echo hi > out.txt; echo again >> out.txt; cat out.txt"}
{"id": "redir-stderr-file", "cmd": "ls missing-dir 2> err.txt; test -s err.txt && echo captured"}
{"id": "stderr-to-pipe", "cmd": "ls missing-dir 2>&1 | grep -o 'No such file or directory'"}
{"id": "brace-group-redir", "cmd": "{ echo brace1; echo brace2; } > group.txt; cat group.txt"}
{"id": "subshell-simple", "cmd": "(echo subshell) && echo after"}
{"id": "cmdsub-nested", "cmd": "echo $(echo nested $(echo deeper))"}
{"id": "cmdsub-multiline", "cmd": "files=$(ls *.txt | sort | head -2); echo \"$files\" | wc -l"}
{"id": "cmdsub-grep", "cmd": "n=$(grep -c INFO logs/app.log); echo \"count=$n\""}
{"id": "basename-pwd", "cmd": "echo \"$(basename \"$PWD\")\""}
{"id": "set-e-false", "cmd": "set -e; false; echo unreachable"}
{"id": "set-e-true", "cmd": "set -e; true; echo reached"}
{"id": "pipefail", "cmd": "set -o pipefail; false | true; echo \"code=$?\""}
{"id": "yes-head", "cmd": "yes | head -3"}
{"id": "read-loop", "cmd": "printf 'a\\nb\\n' | while read l; do echo \"got:$l\"; done"}
{"id": "exit-code", "cmd": "echo start; exit 3"}
{"id": "child-bash", "cmd": "bash -c 'echo child'"}
{"id": "command-v", "cmd": "command -v ls > /dev/null && echo has-ls"}
{"id": "type-t", "cmd": "type -t ls"}
{"id": "cond-pattern", "cmd": "[[ \"abc\" == a?c ]] && echo pattern-match"}
{"id": "cond-numeric", "cmd": "[[ \"5\" -gt 3 ]] && echo gt"}
{"id": "test-dir", "cmd": "test -d src && echo isdir"}
{"id": "echo-n", "cmd": "echo -n \"no-newline\"; echo \"|end\""}
{"id": "printf-pad", "cmd": "printf '%05d\\n' 42"}
{"id": "ifs-split", "cmd": "IFS=,; set -- a,b,c; echo $1"}
{"id": "glob-all", "cmd": "echo *"}
{"id": "ls-dir", "cmd": "ls -1 src/"}
{"id": "mkdir-touch-find", "cmd": "mkdir -p deep/nested/dir && touch deep/nested/dir/f.txt && find deep -type f"}
{"id": "cp-diff", "cmd": "cp a.txt copy.txt && diff a.txt copy.txt && echo identical"}
{"id": "mv-ls", "cmd": "mv b.txt moved.txt && ls moved.txt"}
{"id": "rm-check", "cmd": "cp a.txt c2.txt && rm c2.txt && ls c2.txt 2>/dev/null; echo \"gone rc=$?\""}
{"id": "background-wait", "cmd": "(sleep 0.1; echo bg) & wait; echo done"}
{"id": "procsub-diff", "cmd": "diff <(echo a) <(echo a) && echo same"}
{"id": "procsub-comm", "cmd": "comm -12 <(printf '1\\n2\\n3\\n') <(printf '2\\n3\\n4\\n')"}
{"id": "export-child", "cmd": "export FOO=bar; bash -c 'echo $FOO'"}
{"id": "xargs-n1", "cmd": "printf 'a b c' | xargs -n1 echo"}
{"id": "awk-begin", "cmd": "awk 'BEGIN{printf \"%.2f\\n\", 10/3}'"}
{"id": "python-child", "cmd": "python3 -c 'print(6*7)'"}
{"id": "node-child", "cmd": "node -e 'console.log(\"js\")'"}
{"id": "tar-roundtrip", "cmd": "tar -czf arch.tgz src && tar -tzf arch.tgz | sort"}
{"id": "tee-multi", "cmd": "echo 'x' | tee t1.txt t2.txt && cat t1.txt t2.txt"}
{"id": "trap-exit", "cmd": "trap 'echo trapped' EXIT; echo body"}
{"id": "quoting-mixed", "cmd": "printf '%s\\n' \"double \\\"quoted\\\" and 'single'\""}
{"id": "escapes", "cmd": "echo \"backslash: \\\\ dollar: \\$HOME\""}
{"id": "line-continuation", "cmd": "echo one \\\ntwo"}
{"id": "func-return", "cmd": "f(){ return 4; }; f; echo \"rc=$?\""}
{"id": "shift-args", "cmd": "set -- a b c; shift; echo \"$1 $#\""}
{"id": "getopts", "cmd": "f() { while getopts 'x:y' o; do echo \"o=$o a=$OPTARG\"; done; }; f -x val -y"}
{"id": "declare-i", "cmd": "declare -i n=5; n+=2; echo $n"}
{"id": "dirname-basename", "cmd": "dirname src/main.py; basename src/main.py .py"}
{"id": "realpath", "cmd": "realpath a.txt"}
{"id": "stat-size", "cmd": "stat -c %s a.txt"}
{"id": "od-herestring", "cmd": "od -c <<< 'hi' | head -1"}
{"id": "dev-null", "cmd": "echo discarded > /dev/null; echo kept"}
{"id": "fd-dup-order", "cmd": "{ echo to-out; echo to-err >&2; } 2>/dev/null"}
{"id": "curl-sh-shape", "cmd": "printf 'echo piped-script\\n' | bash"}
{"id": "seq-paste", "cmd": "seq 1 4 | paste -sd+ | bc 2>/dev/null || seq 1 4 | paste -sd,"}
{"id": "nested-quotes-cmdsub", "cmd": "echo \"outer $(echo \"inner $(echo deepest)\")\""}
{"id": "utf8-read-passthru", "cmd": "printf 'F\\305\\221tan\\303\\272s\\303\\255tv\\303\\241ny\\n' | { read x; printf '%s\\n' \"$x\"; }"}
{"id": "utf8-while-read-file", "cmd": "printf 'caf\\303\\251.crt\\nna\\303\\257ve.pem\\n' > names.txt; while read n; do echo \"got:$n\"; done < names.txt"}
{"id": "utf8-cmdsub-roundtrip", "cmd": "x=$(printf '\\303\\251l\\303\\251gant'); echo \"$x\""}
{"id": "errexit-if-andlist", "cmd": "set -e; if true; then false && true; fi; echo survived"}
{"id": "errexit-brace-andlist", "cmd": "set -e; { false && true; }; echo grouped-ok"}
{"id": "errexit-if-bang", "cmd": "set -e; if true; then ! true; fi; echo bang-ok"}
{"id": "errexit-fn-status", "cmd": "set -e; f() { false && true; }; f && echo unreachable || echo fn-failed"}