Working with text

Word count

Word (-w), line (-l), character (-m) and byte (-c) count for file or piped input

<input> | wc

Sort

Sort lines of text in standard or reverse order (-r)

<input> | sort

Sort by numerical (-n) or general numerical values (-g handles floating points)

<input> | sort -n
<input> | sort -g

Unique

Filter out repeat / duplicate lines that are adjacent (-c to output repeated count for each entry)

<input> | uniq
<input> | uniq -c

Sort lines first to position duplicate lines together for removal

<input> | sort | uniq

Show ordered count of each repeated line (filtering out single non-repeated lines)

<input> | uniq -c | grep -v '^ *1 ' | sort -nr

Text replace

Pipe text into tr to replace content (eg. replace commas with new lines)

<input> | tr <search> <replace>
<input> | tr ',' '\n'

Text extract

Output printable strings contained in file (useful for extracting metadata from binary files)

strings <file>

Grep

Search and output matching strings (case insensitive -i, display line numbers -n)

grep '<search-string>' <path>
grep -in '<search-string>' <path>

Search and output multiple matching strings

grep '<search-string-1>\|<search-string-2>\|<search-string-3>' <path>

Pipe content into grep (eg. via cat or echo)

cat <file> | grep '<string>'
echo '<text>' | grep '<string>'

Show context lines after (-A), before (-B) or both sides (-C) of search results

grep '<string>' -C <line-count>

awk

Print the first (or second $2, third $3 etc) field / word token for each line

awk '{print $1}' <path>

Print lines longer the <length> characters (eg. 200)

awk 'length($0) > <length>' <path>
awk 'length($0) > 200' <path>