Search and Text Processing Commands

echo "hello" | base32
echo "NBSWY3DP" | base32 -d

echo "hello" | base64
echo "aGVsbG8K" | base64 -d

echo -e "name age\nalice 30\nbob 25" | column -t

comm file1.txt file2.txt
comm -12 file1.txt file2.txt                # lines common to both
comm -23 file1.txt file2.txt                # lines only in file1

echo "a:b:c" | cut -d: -f2                 # b
cut -f1,3 -d',' data.csv
cut -c1-10 file.txt                         # first 10 characters

diff file1.txt file2.txt
diff -u old.txt new.txt                     # unified format

grep "error" log.txt
grep -r "TODO" src/
grep -n -i "warning" *.log                  # line numbers, case-insensitive
grep -c "pattern" file.txt                  # count matches
grep -v "debug" log.txt                     # invert match

head file.txt                               # first 10 lines
head -n 5 file.txt
head -c 100 file.txt                        # first 100 bytes

join file1.txt file2.txt
join -t',' -1 2 -2 1 a.csv b.csv

nl file.txt
nl -ba file.txt                             # number all lines including blanks

paste names.txt scores.txt
paste -d',' col1.txt col2.txt               # comma delimiter
paste -s file.txt                           # serial mode

printf "%s is %d years old\n" "Alice" 30
printf "%05d\n" 42                          # 00042
printf -v msg "%s-%02d" "build" 7; echo "$msg"

echo "hello" | rev                          # olleh

sed 's/old/new/' file.txt
sed -i 's/foo/bar/g' file.txt               # in-place
sed -n '5,10p' file.txt                     # print lines 5-10
sed '/^#/d' config.txt                      # delete comment lines

seq 5                                       # 1 2 3 4 5
seq 2 10                                    # 2 through 10
seq 0 2 10                                  # 0 2 4 6 8 10

sort file.txt
sort -n numbers.txt                         # numeric sort
sort -r file.txt                            # reverse
sort -u file.txt                            # unique lines only
sort -t',' -k2 data.csv                     # sort by second field

split -l 100 big.txt chunk_                 # 100 lines per file
split -b 1m big.bin part_                   # 1 MB per file

tac file.txt

tail file.txt                               # last 10 lines
tail -n 20 file.txt
tail -c 100 file.txt                        # last 100 bytes

echo "hello" | tee output.txt
echo "hello" | tee -a output.txt            # append
echo "hello" | tee a.txt b.txt              # write to multiple files

echo "hello" | tr a-z A-Z                   # HELLO
echo "hello  world" | tr -s ' '            # squeeze spaces
echo "hello123" | tr -d '0-9'              # delete digits

sort file.txt | uniq
sort file.txt | uniq -c                     # count occurrences
sort file.txt | uniq -d                     # only duplicates

wc file.txt
wc -l file.txt                              # line count only
wc -w file.txt                              # word count only

xan headers data.csv
xan count data.csv
xan select 'name,email' data.csv
xan select 'vec_*' data.csv                # glob column selection
xan filter 'age > 30' data.csv             # expression filtering
xan groupby region 'sum(amount) as total'  # grouped aggregation
xan explode tags data.csv                  # reshape rows
xan join id left.csv user_id right.csv     # multi-file join
xan to json data.csv                       # CSV -> JSON
xan slice -s 1 -e 3 data.csv               # row slicing
xan flatten -l 2 data.csv                  # vertical record view