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author | Johannes Stoelp <johannes.stoelp@gmail.com> | 2024-05-01 14:57:52 +0200 |
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committer | Johannes Stoelp <johannes.stoelp@gmail.com> | 2024-05-01 14:57:52 +0200 |
commit | b737cc8ca5bb8ca5e07cd0151d678a7b4b10d5cb (patch) | |
tree | 86814d8fb3557ea2cbf73892dd0ec4e590e854de /src/tools | |
parent | 50e07a8bca68d2f568df44166fa94383141c2696 (diff) | |
download | notes-b737cc8ca5bb8ca5e07cd0151d678a7b4b10d5cb.tar.gz notes-b737cc8ca5bb8ca5e07cd0151d678a7b4b10d5cb.zip |
cli: add new group for cli foo tools
Diffstat (limited to 'src/tools')
-rw-r--r-- | src/tools/README.md | 4 | ||||
-rw-r--r-- | src/tools/awk.md | 197 | ||||
-rw-r--r-- | src/tools/column.md | 10 | ||||
-rw-r--r-- | src/tools/sed.md | 102 | ||||
-rw-r--r-- | src/tools/sort.md | 35 |
5 files changed, 0 insertions, 348 deletions
diff --git a/src/tools/README.md b/src/tools/README.md index 41584d0..5dbb7f0 100644 --- a/src/tools/README.md +++ b/src/tools/README.md @@ -2,7 +2,6 @@ - [tmux](./tmux.md) - [git](./git.md) -- [awk](./awk.md) - [emacs](./emacs.md) - [gpg](./gpg.md) - [gdb](./gdb.md) @@ -12,7 +11,4 @@ - [pacman](./pacman.md) - [dot](./dot.md) - [ffmpeg](./ffmpeg.md) -- [column](./column.md) -- [sort](./sort.md) -- [sed](./sed.md) - [gnuplot](./gnuplot.md) diff --git a/src/tools/awk.md b/src/tools/awk.md deleted file mode 100644 index d6f6c9c..0000000 --- a/src/tools/awk.md +++ /dev/null @@ -1,197 +0,0 @@ -# awk(1) - -```markdown -awk [opt] program [input] - -F <sepstr> field separator string (can be regex) - program awk program - input file or stdin if not file given -``` - -## Input processing - -Input is processed in two stages: -1. Splitting input into a sequence of `records`. - By default split at `newline` character, but can be changed via the - builtin `RS` variable. -2. Splitting a `record` into `fields`. By default strings without `whitespace`, - but can be changed via the builtin variable `FS` or command line option - `-F`. - -Fields are accessed as follows: -- `$0` whole `record` -- `$1` field one -- `$2` field two -- ... - -## Program - -An `awk` program is composed of pairs of the form: -```markdown -pattern { action } -``` -The program is run against each `record` in the input stream. If a `pattern` -matches a `record` the corresponding `action` is executed and can access the -`fields`. - -```markdown -INPUT - | - v -record ----> ∀ pattern matched - | | - v v -fields ----> run associated action -``` - -Any valid awk `expr` can be a `pattern`. - -An example is the regex pattern `/abc/ { print $1 }` which prints the first -field if the record matches the regex `/abc/`. This form is actually a short -version for `$0 ~ /abc/ { print $1 }`, see the regex comparison operator -below. - -### Special pattern - -awk provides two special patterns, `BEGIN` and `END`, which can be used -multiple times. Actions with those patterns are **executed exactly once**. -- `BEGIN` actions are run before processing the first record -- `END` actions are run after processing the last record - -### Special variables - -- `RS` _record separator_: first char is the record separator, by default - <newline> -- `FS` _field separator_: regex to split records into fields, by default - <space> -- `NR` _number record_: number of current record -- `NF` _number fields_: number of fields in the current record - -### Special statements & functions - -- `printf "fmt", args...` - - Print format string, args are comma separated. - - `%s` string - - `%d` decimal - - `%x` hex - - `%f` float - - Width can be specified as `%Ns`, this reserves `N` chars for a string. - For floats one can use `%N.Mf`, `N` is the total number including `.` and - `M`. - -- `sprintf("fmt", expr, ...)` - - Format the expressions according to the format string. Similar as `printf`, - but this is a function and return value can be assigned to a variable. - -- `strftime("fmt")` - - Print time stamp formatted by `fmt`. - - `%Y` full year (eg 2020) - - `%m` month (01-12) - - `%d` day (01-31) - - `%F` alias for `%Y-%m-%d` - - `%H` hour (00-23) - - `%M` minute (00-59) - - `%S` second (00-59) - - `%T` alias for `%H:%M:%S` - -- `S ~ R`, `S !~ R` - - The regex comparison operator, where the former returns true if the string - `S` matches the regex `R`, and the latter is the negated form. - The regex can be either a - [constant](https://www.gnu.org/software/gawk/manual/html_node/Regexp-Usage.html) - or [dynamic]( - https://www.gnu.org/software/gawk/manual/html_node/Computed-Regexps.html) - regex. - -## Examples - -### Filter records -```bash -awk 'NR%2 == 0 { print $0 }' <file> -``` -The pattern `NR%2 == 0` matches every second record and the action `{ print $0 }` -prints the whole record. - -### Negative patterns -```bash -awk '!/^#/ { print $1 }' <file> -``` -Matches records not starting with `#`. - -### Range patterns -```bash -echo -e "a\nFOO\nb\nc\nBAR\nd" | \ - awk '/FOO/,/BAR/ { print }' -``` -`/FOO/,/BAR/` define a range pattern of `begin_pattern, end_pattern`. When -`begin_pattern` is matched the range is **turned on** and when the -`end_pattern` is matched the range is **turned off**. This matches every record -in the range _inclusive_. - -An _exclusive_ range must be handled explicitly, for example as follows. -```bash -echo -e "a\nFOO\nb\nc\nBAR\nd" | \ - awk '/FOO/,/BAR/ { if (!($1 ~ "FOO") && !($1 ~ "BAR")) { print } }' -``` - -### Access last fields in records -```bash -echo 'a b c d e f' | awk '{ print $NF $(NF-1) }' -``` -Access last fields with arithmetic on the `NF` number of fields variable. - -### Split on multiple tokens -```bash -echo 'a,b;c:d' | awk -F'[,;:]' '{ printf "1=%s | 4=%s\n", $1, $4 }' -``` -Use regex as field separator. - -### Capture in variables -```bash -# /proc/<pid>/status -# Name: cat -# ... -# VmRSS: 516 kB -# ... - -for f in /proc/*/status; do - cat $f | awk ' - /^VmRSS/ { rss = $2/1024 } - /^Name/ { name = $2 } - END { printf "%16s %6d MB\n", name, rss }'; -done | sort -k2 -n -``` -We capture values from `VmRSS` and `Name` into variables and print them at the -`END` once processing all records is done. - -### Capture in array -```bash -echo 'a 10 -b 2 -b 4 -a 1' | awk '{ - vals[$1] += $2 - cnts[$1] += 1 -} -END { - for (v in vals) - printf "%s %d\n", v, vals[v] / cnts [v] -}' -``` -Capture keys and values from different columns and some up the values. -At the `END` we compute the average of each key. - -### Run shell command and capture output -```bash -cat /proc/1/status | awk ' - /^Pid/ { - "ps --no-header -o user " $2 | getline user; - print user - }' -``` -We build a `ps` command line and capture the first line of the processes output -in the `user` variable and then print it. diff --git a/src/tools/column.md b/src/tools/column.md deleted file mode 100644 index 4a3b2c4..0000000 --- a/src/tools/column.md +++ /dev/null @@ -1,10 +0,0 @@ -# column(1) - -## Examples -```sh -# Show as table (aligned columns), with comma as delimiter from stdin. -echo -e 'a,b,c\n111,22222,33' | column -t -s ',' - -# Show file as table. -column -t -s ',' test.csv -``` diff --git a/src/tools/sed.md b/src/tools/sed.md deleted file mode 100644 index 5b5f741..0000000 --- a/src/tools/sed.md +++ /dev/null @@ -1,102 +0,0 @@ -# sed(1) - -``` -sed [opts] [script] [file] - opts: - -i edit file in place - -i.bk edit file in place and create backup file - (with .bk suffix, can be specified differently) - --follow-symlinks - follow symlinks when editing in place - -e SCRIPT add SCRIPT to commands to be executed - (can be specified multiple times) - -f FILE add content of FILE to command to be executed - - --debug annotate program execution -``` - -## Examples -### Delete lines -```sh -# Delete two lines. -echo -e 'aa\nbb\ncc\ndd' | sed '1d;3d' -# bb -# dd - -# Delete last ($) line. -echo -e 'aa\nbb\ncc\ndd' | sed '$d' -# aa -# bb -# cc - -# Delete range of lines. -echo -e 'aa\nbb\ncc\ndd' | sed '1,3d' -# dd - -# Delete lines matching pattern. -echo -e 'aa\nbb\ncc\ndd' | sed '/bb/d' -# aa -# cc -# dd - -# Delete lines NOT matching pattern. -echo -e 'aa\nbb\ncc\ndd' | sed '/bb/!d' -# bb -``` - -### Insert lines -```sh -# Insert before line. -echo -e 'aa\nbb' | sed '2iABC' -# aa -# ABC -# bb - -# Insert after line. -echo -e 'aa\nbb' | sed '2aABC' -# aa -# bb -# ABC - -# Replace line. -echo -e 'aa\nbb' | sed '2cABC' -# aa -# ABC - -# Insert before pattern match. -echo -e 'aa\nbb' | sed '/bb/i 123' -# aa -# 123 -# bb -``` - -### Substitute lines -```sh -# Substitute by regex. -echo -e 'aafooaa\ncc' | sed 's/foo/MOOSE/' -# aaMOOSEaa -# cc -``` - -### Multiple scripts -```sh -echo -e 'foo\nbar' | sed -e 's/foo/FOO/' -e 's/FOO/BAR/' -# BAR -# bar -``` - -### Edit inplace through symlink -```sh -touch file -ln -s file link -ls -l link -# lrwxrwxrwx 1 johannst johannst 4 Feb 7 23:02 link -> file - -sed -i --follow-symlinks '1iabc' link -ls -l link -# lrwxrwxrwx 1 johannst johannst 4 Feb 7 23:02 link -> file - -sed -i '1iabc' link -ls -l link -# -rw-r--r-- 1 johannst johannst 0 Feb 7 23:02 link -``` diff --git a/src/tools/sort.md b/src/tools/sort.md deleted file mode 100644 index e74b490..0000000 --- a/src/tools/sort.md +++ /dev/null @@ -1,35 +0,0 @@ -# sort(1) - -``` -sort [opts] [file] - opts: - -r reverse output - -b ignore leading blanks - - -n sort by numeric - -h sort by human numeric - -V sort by version - - -k<N> sort by Nth key - -t<S> field separator -``` - -## Examples -```sh -# Sort by directory sizes. -du -sh * | sort -h -``` - -```sh -# Sort numeric by second key. -# The default key separator is non-blank to blank transition. -echo 'a 4 -d 10 -c 21' | sort -k2 -n - -# Sort numeric by second key, split at comma. -echo 'a,4 -d,10 -c,21' | sort -k2 -n -t, -``` -> Use `--debug` to annotate part of the line used to sort and hence debug the key usage. |