Word (-w), line (-l), character (-m) and byte (-c) count for file or piped input
<input> | wc
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
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
Pipe text into tr to replace content (eg. replace commas with new lines)
<input> | tr <search> <replace>
<input> | tr ',' '\n'
Output printable strings contained in file (useful for extracting metadata from binary files)
strings <file>
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>
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>