| cat file1 file2 ... | command <> file1_in.txt_or_file1_out.txt | general syntax for text manipulation using PIPE, STDIN and STDOUT |
| cat file1 | command( sed, grep, awk, grep, etc...) > result.txt | general syntax to manipulate a text of a file, and write result to a new file |
| cat file1 | command( sed, grep, awk, grep, etc...) >> result.txt | general syntax to manipulate a text of a file and append result in existing file |
| grep Aug /var/log/messages | look up words "Aug" on file '/var/log/messages' |
| grep ^Aug /var/log/messages | look up words that begin with "Aug" on file '/var/log/messages' |
| grep [0-9] /var/log/messages | select from file '/var/log/messages' all lines that contain numbers |
| grep Aug -R /var/log/* | search string "Aug" at directory '/var/log' and below |
| sed 's/stringa1/stringa2/g' example.txt | replace "string1" with "string2" in example.txt |
| sed '/^$/d' example.txt | remove all blank lines from example.txt |
| sed '/ *#/d; /^$/d' example.txt | remove comments and blank lines from example.txt |
| echo 'esempio' | tr '[:lower:]' '[:upper:]' | convert from lower case in upper case |
| sed -e '1d' result.txt | eliminates the first line from file example.txt |
| sed -n '/stringa1/p' | view only lines that contain the word "string1" |
| sed -e 's/ *$//' example.txt | remove empty characters at the end of each row |
| sed -e 's/stringa1//g' example.txt | remove only the word "string1" from text and leave intact all |
| sed -n '1,5p;5q' example.txt | view from 1th to 5th row |
| sed -n '5p;5q' example.txt | view row number 5 |
| sed -e 's/00*/0/g' example.txt | replace more zeros with a single zero |
| cat -n file1 | number row of a file |
| cat example.txt | awk 'NR%2==1' | remove all even lines from example.txt |
| echo a b c | awk '{print $1}' | view the first column of a line |
| echo a b c | awk '{print $1,$3}' | view the first and third column of a line |
| paste file1 file2 | merging contents of two files for columns |
| paste -d '+' file1 file2 | merging contents of two files for columns with '+' delimiter on the center |
| sort file1 file2 | sort contents of two files |
| sort file1 file2 | uniq | sort contents of two files omitting lines repeated |
| sort file1 file2 | uniq -u | sort contents of two files by viewing only unique line |
| sort file1 file2 | uniq -d | sort contents of two files by viewing only duplicate line |
| comm -1 file1 file2 | compare contents of two files by deleting only unique lines from 'file1' |
| comm -2 file1 file2 | compare contents of two files by deleting only unique lines from 'file2' |
| comm -3 file1 file2 | compare contents of two files by deleting only the lines that appear on both files |
