Difference between revisions of "Linux/Unix:Find and Replace"
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==cat== | ==cat== | ||
| − | ==head tail== | + | ==head & tail== |
| − | Show only top or | + | Show only top or bottom lines from a file |
;tail <num> filename | ;tail <num> filename | ||
:Show the last <num> lines from filename. 10 is the default | :Show the last <num> lines from filename. 10 is the default | ||
| + | ;tail -f filename | ||
| + | :Keep showing all files appended to the file | ||
;head -<num> filename | ;head -<num> filename | ||
:Show the first <num> lines from filename. 10 is the default | :Show the first <num> lines from filename. 10 is the default | ||
| − | ;tail +<num> filename | + | ;head -n -<num> filename |
| + | :Show all except the last <num> lines from filename | ||
| + | ;tail -n +<num> filename | ||
:Show all lines from line <num> onwards | :Show all lines from line <num> onwards | ||
| − | ;tail +<lineno> filename|head -<num> | + | ;tail -n +<lineno> filename|head -<num> |
:show <num> lines starting at <lineno> | :show <num> lines starting at <lineno> | ||
| Line 19: | Line 23: | ||
==strings== | ==strings== | ||
| + | ;strings filename | ||
| + | :Try to show the file content in printable characters | ||
==more less== | ==more less== | ||
| Line 34: | Line 40: | ||
==grep== | ==grep== | ||
| − | == | + | ==[[Sed]]== |
| − | + | See the [[Sed]] page. | |
;s/pattern/newstring/ | ;s/pattern/newstring/ | ||
:In each line replace first occurrence of pattern with newstring. /g at the end replaces all occurrences of pattern. | :In each line replace first occurrence of pattern with newstring. /g at the end replaces all occurrences of pattern. | ||
| Line 42: | Line 48: | ||
:Delete each line matching pattern. | :Delete each line matching pattern. | ||
| − | == | + | ==[[Awk]]== |
| + | See the [[Awk]] page | ||
==read== | ==read== | ||
Latest revision as of 16:09, 15 November 2022
cat
head & tail
Show only top or bottom lines from a file
- tail <num> filename
- Show the last <num> lines from filename. 10 is the default
- tail -f filename
- Keep showing all files appended to the file
- head -<num> filename
- Show the first <num> lines from filename. 10 is the default
- head -n -<num> filename
- Show all except the last <num> lines from filename
- tail -n +<num> filename
- Show all lines from line <num> onwards
- tail -n +<lineno> filename|head -<num>
- show <num> lines starting at <lineno>
fold
strings
- strings filename
- Try to show the file content in printable characters
more less
tr
- tr "[:upper:]" "[:lower:]"
- tr "[abc]" "[xyz]"
- Transtlate, make all lowercase
- replace all a's with y, all b's with y and all c's with z, works from stdin to stdout. All sort of translations can be done
- tr -d <char>
- Delete <char> from standard input
grep
Sed
See the Sed page.
- s/pattern/newstring/
- In each line replace first occurrence of pattern with newstring. /g at the end replaces all occurrences of pattern.
- s/pattern/d
- Delete each line matching pattern.
Awk
See the Awk page