how to delete line numbers in a code block?

Question

Generally codes published in web pages contains line numbers. When I copy and paste code into text editor (though some text editors remove line numbers automatically, but somtimes it doesn't work), it gets tiring to remove line numbers.

There must be some sed, awk or other linux parsing tools to deal with it.

Let's say I have below code, how can I remove line numbers safely with above mentioned tools?

   1 /*
   2  * Beep using pcm
   3  *
   4  * Copyright (c) by Takashi Iwai <[email protected]>
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  */
  20 
  21 #include <asm/io.h>
  22 #include <asm/irq.h>
  23 #include <linux/init.h>
  24 #include <linux/slab.h>
  25 #include <linux/input.h>
  26 #include <linux/pci.h>
  27 #include <linux/dma-mapping.h>
  28 #include <sound/core.h>
  29 #include <sound/control.h>
  30 #include "pmac.h"
  31 
  32 struct pmac_beep {
  33         int running;            /* boolean */
  34         int volume;             /* mixer volume: 0-100 */
  35         int volume_play;        /* currently playing volume */
  36         int hz;
  37         int nsamples;
  38         short *buf;             /* allocated wave buffer */
  39         dma_addr_t addr;        /* physical address of buffer */
  40         struct input_dev *dev;
  41 };
  42 
  43 /*
  44  * stop beep if running
  45  */
  46 void snd_pmac_beep_stop(struct snd_pmac *chip)
  47 {
  48         struct pmac_beep *beep = chip->beep;
  49         if (beep && beep->running) {
  50                 beep->running = 0;
  51                 snd_pmac_beep_dma_stop(chip);
  52         }
  53 }
  54 
  55 /*
  56  * Stuff for outputting a beep.  The values range from -327 to +327
  57  * so we can multiply by an amplitude in the range 0..100 to get a
  58  * signed short value to put in the output buffer.
  59  */
  60 static short beep_wform[256] = {
  61         0,      40,     79,     117,    153,    187,    218,    245,
  62         269,    288,    304,    316,    323,    327,    327,    324,
  63         318,    310,    299,    288,    275,    262,    249,    236,
  64         224,    213,    204,    196,    190,    186,    183,    182,
  65         182,    183,    186,    189,    192,    196,    200,    203,
  66         206,    208,    209,    209,    209,    207,    204,    201,
  67         197,    193,    188,    183,    179,    174,    170,    166,
  68         163,    161,    160,    159,    159,    160,    161,    162,
  69         164,    166,    168,    169,    171,    171,    171,    170,
  70         169,    167,    163,    159,    155,    150,    144,    139,
  71         133,    128,    122,    117,    113,    110,    107,    105,
  72         103,    103,    103,    103,    104,    104,    105,    105,
  73         105,    103,    101,    97,     92,     86,     78,     68,
  74         58,     45,     32,     18,     3,      -11,    -26,    -41,
  75         -55,    -68,    -79,    -88,    -95,    -100,   -102,   -102,
  76         -99,    -93,    -85,    -75,    -62,    -48,    -33,    -16,
  77         0,      16,     33,     48,     62,     75,     85,     93,
  78         99,     102,    102,    100,    95,     88,     79,     68,
  79         55,     41,     26,     11,     -3,     -18,    -32,    -45,
  80         -58,    -68,    -78,    -86,    -92,    -97,    -101,   -103,
  81         -105,   -105,   -105,   -104,   -104,   -103,   -103,   -103,
  82         -103,   -105,   -107,   -110,   -113,   -117,   -122,   -128,
  83         -133,   -139,   -144,   -150,   -155,   -159,   -163,   -167,
  84         -169,   -170,   -171,   -171,   -171,   -169,   -168,   -166,
  85         -164,   -162,   -161,   -160,   -159,   -159,   -160,   -161,
  86         -163,   -166,   -170,   -174,   -179,   -183,   -188,   -193,
  87         -197,   -201,   -204,   -207,   -209,   -209,   -209,   -208,
  88         -206,   -203,   -200,   -196,   -192,   -189,   -186,   -183,
  89         -182,   -182,   -183,   -186,   -190,   -196,   -204,   -213,
  90         -224,   -236,   -249,   -262,   -275,   -288,   -299,   -310,
  91         -318,   -324,   -327,   -327,   -323,   -316,   -304,   -288,
  92         -269,   -245,   -218,   -187,   -153,   -117,   -79,    -40,
  93 };
  94 
  95 #define BEEP_SRATE      22050   /* 22050 Hz sample rate */
  96 #define BEEP_BUFLEN     512
  97 #define BEEP_VOLUME     15      /* 0 - 100 */
  98 
  99 static int snd_pmac_beep_event(struct input_dev *dev, unsigned int type,
 100                                unsigned int code, int hz)
 101 {
 102         struct snd_pmac *chip;
 103         struct pmac_beep *beep;
 104         unsigned long flags;
 105         int beep_speed = 0;
 106         int srate;
 107         int period, ncycles, nsamples;
 108         int i, j, f;
 109         short *p;
 110 
 111         if (type != EV_SND)
 112                 return -1;
 113 
 114         switch (code) {
 115         case SND_BELL: if (hz) hz = 1000;
 116         case SND_TONE: break;
 117         default: return -1;
 118         }
 119 
 120         chip = input_get_drvdata(dev);
 121         if (! chip || (beep = chip->beep) == NULL)
 122                 return -1;
 123 
 124         if (! hz) {
 125                 spin_lock_irqsave(&chip->reg_lock, flags);
 126                 if (beep->running)
 127                         snd_pmac_beep_stop(chip);
 128                 spin_unlock_irqrestore(&chip->reg_lock, flags);
 129                 return 0;
 130         }
 131 
 132         beep_speed = snd_pmac_rate_index(chip, &chip->playback, BEEP_SRATE);
 133         srate = chip->freq_table[beep_speed];
 134 
 135         if (hz <= srate / BEEP_BUFLEN || hz > srate / 2)
 136                 hz = 1000;
 137 
 138         spin_lock_irqsave(&chip->reg_lock, flags);
 139         if (chip->playback.running || chip->capture.running || beep->running) {
 140                 spin_unlock_irqrestore(&chip->reg_lock, flags);
 141                 return 0;
 142         }
 143         beep->running = 1;
 144         spin_unlock_irqrestore(&chip->reg_lock, flags);
 145 
 146         if (hz == beep->hz && beep->volume == beep->volume_play) {
 147                 nsamples = beep->nsamples;
 148         } else {
 149                 period = srate * 256 / hz;      /* fixed point */
 150                 ncycles = BEEP_BUFLEN * 256 / period;
 151                 nsamples = (period * ncycles) >> 8;
 152                 f = ncycles * 65536 / nsamples;
 153                 j = 0;
 154                 p = beep->buf;
 155                 for (i = 0; i < nsamples; ++i, p += 2) {
 156                         p[0] = p[1] = beep_wform[j >> 8] * beep->volume;
 157                         j = (j + f) & 0xffff;
 158                 }
 159                 beep->hz = hz;
 160                 beep->volume_play = beep->volume;
 161                 beep->nsamples = nsamples;
 162         }
 163 
 164         spin_lock_irqsave(&chip->reg_lock, flags);
 165         snd_pmac_beep_dma_start(chip, beep->nsamples * 4, beep->addr, beep_speed);
 166         spin_unlock_irqrestore(&chip->reg_lock, flags);
 167         return 0;
 168 }
 169 
 170 /*
 171  * beep volume mixer
 172  */
 173 
 174 static int snd_pmac_info_beep(struct snd_kcontrol *kcontrol,
 175                               struct snd_ctl_elem_info *uinfo)
 176 {
 177         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 178         uinfo->count = 1;
 179         uinfo->value.integer.min = 0;
 180         uinfo->value.integer.max = 100;
 181         return 0;
 182 }
 183 
 184 static int snd_pmac_get_beep(struct snd_kcontrol *kcontrol,
 185                              struct snd_ctl_elem_value *ucontrol)
 186 {
 187         struct snd_pmac *chip = snd_kcontrol_chip(kcontrol);
 188         if (snd_BUG_ON(!chip->beep))
 189                 return -ENXIO;
 190         ucontrol->value.integer.value[0] = chip->beep->volume;
 191         return 0;
 192 }
 193 
 194 static int snd_pmac_put_beep(struct snd_kcontrol *kcontrol,
 195                              struct snd_ctl_elem_value *ucontrol)
 196 {
 197         struct snd_pmac *chip = snd_kcontrol_chip(kcontrol);
 198         unsigned int oval, nval;
 199         if (snd_BUG_ON(!chip->beep))
 200                 return -ENXIO;
 201         oval = chip->beep->volume;
 202         nval = ucontrol->value.integer.value[0];
 203         if (nval > 100)
 204                 return -EINVAL;
 205         chip->beep->volume = nval;
 206         return oval != chip->beep->volume;
 207 }
 208 
 209 static struct snd_kcontrol_new snd_pmac_beep_mixer = {
 210         .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 211         .name = "Beep Playback Volume",
 212         .info = snd_pmac_info_beep,
 213         .get = snd_pmac_get_beep,
 214         .put = snd_pmac_put_beep,
 215 };
 216 
 217 /* Initialize beep stuff */
 218 int __devinit snd_pmac_attach_beep(struct snd_pmac *chip)
 219 {
 220         struct pmac_beep *beep;
 221         struct input_dev *input_dev;
 222         struct snd_kcontrol *beep_ctl;
 223         void *dmabuf;
 224         int err = -ENOMEM;
 225 
 226         beep = kzalloc(sizeof(*beep), GFP_KERNEL);
 227         if (! beep)
 228                 return -ENOMEM;
 229         dmabuf = dma_alloc_coherent(&chip->pdev->dev, BEEP_BUFLEN * 4,
 230                                     &beep->addr, GFP_KERNEL);
 231         input_dev = input_allocate_device();
 232         if (! dmabuf || ! input_dev)
 233                 goto fail1;
 234 
 235         /* FIXME: set more better values */
 236         input_dev->name = "PowerMac Beep";
 237         input_dev->phys = "powermac/beep";
 238         input_dev->id.bustype = BUS_ADB;
 239         input_dev->id.vendor = 0x001f;
 240         input_dev->id.product = 0x0001;
 241         input_dev->id.version = 0x0100;
 242 
 243         input_dev->evbit[0] = BIT_MASK(EV_SND);
 244         input_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE);
 245         input_dev->event = snd_pmac_beep_event;
 246         input_dev->dev.parent = &chip->pdev->dev;
 247         input_set_drvdata(input_dev, chip);
 248 
 249         beep->dev = input_dev;
 250         beep->buf = dmabuf;
 251         beep->volume = BEEP_VOLUME;
 252         beep->running = 0;
 253 
 254         beep_ctl = snd_ctl_new1(&snd_pmac_beep_mixer, chip);
 255         err = snd_ctl_add(chip->card, beep_ctl);
 256         if (err < 0)
 257                 goto fail1;
 258 
 259         chip->beep = beep;
 260 
 261         err = input_register_device(beep->dev);
 262         if (err)
 263                 goto fail2;
 264  
 265         return 0;
 266  
 267  fail2: snd_ctl_remove(chip->card, beep_ctl);
 268  fail1: input_free_device(input_dev);
 269         if (dmabuf)
 270                 dma_free_coherent(&chip->pdev->dev, BEEP_BUFLEN * 4,
 271                                   dmabuf, beep->addr);
 272         kfree(beep);
 273         return err;
 274 }
 275 
 276 void snd_pmac_detach_beep(struct snd_pmac *chip)
 277 {
 278         if (chip->beep) {
 279                 input_unregister_device(chip->beep->dev);
 280                 dma_free_coherent(&chip->pdev->dev, BEEP_BUFLEN * 4,
 281                                   chip->beep->buf, chip->beep->addr);
 282                 kfree(chip->beep);
 283                 chip->beep = NULL;
 284         }
 285 }
 286 

Solution 1

With awk

awk '{$1="";print $0}' FileName > NewFileName

Explanation:

• awk splits the input/file into fields, with a default delimiter of whitespace.
• $1="" means "set the first field" to nothing. The first field in your text will always be the line number, so we're essentially deleting the line numbers.
• print $0 means "print all fields", so we're printing all the fields, but the first field is now empty and won't be printed.

awk messes up the code formatting though. See this answer for more information on how you might preserve it.

---

With sed

sed 's/^ *[0-9]\+.//g' FileName > NewFileName

Explanation:

• sed 's/<replace this>/<with this>/g'.
• ^ *[0-9]\+. means: match from the beginning of the line (^), then match zero or more spaces ( *), then match a digit between 0 and 9 ([0-9]), match more than one digit (\+), then match any single character (.).
• There's nothing between //, so we're basically replacing what we just matched with nothing, effectively deleting it.

Credit to karel's answer for the sed command.

---

With cut (and sed)

sed 's/^ *//g' FileName | cut -d' ' -f2- > NewFileName

Explanation:

• sed 's/^ *//g', where ^ * means: match from the beginning of the line (^), then match zero or more spaces ( *). We're then replacing what we matched with nothing, to delete it. This sed part is used to remove any leading spaces in the file.
• cut is also a text manipulation program that separates the input into fields (using a default delimiter of tab).
• -d' ' is setting the delimiter to a space, so now the first field is our numbers.
• -f2- means print the second field onwards (the last hyphen - means "onwards").

Solution 2

From the terminal run:

sed 's/ *[0-9]*.//' script > script-no-line-numbers

Solution 3

If you want a method that works in a text editor, then you can use the combination ctrlx + r + k to cut a rectangular area of text in emacs.

Solution 4

In some text editors like Geany or (Notepad++ only in Windows) it can be done easily. Just keep CTRL+ALT and then hold Mouse Left Click and draw a rectangle around numbered area

View more solutions

Comments

[wchargin]

You don't need cat here. Use awk '{$1="";print $0}' < script instead.

[leftaroundabout]

...or sed 's/^[0-9]\+\s//g' script. OTOH, Useless Use Of Cat has something of a tradition. At least the < script alternative is IMO not so clever, because mistyping < for > will overwrite the file.

[Ashish]

Excellent answer. Complete in all respect. Made my day coming across this one right in the morning.

[Sorin]

line numbers are right justified, they may have some spaces before - all your "solutions" are wrong for the file given as a example

[kenn]

@Sorin Actually I used karels solution. It works well, but I haven't heavily tested it yet. I thank you all who post an answer.

[αғsнιη]

Your cut and sed solution is not works at least for this example.

[Alaa Ali]

@KasiyA I've fixed the sed command, and added a sed part to the cat command to remove leading spaces first.

[Alaa Ali]

@Sorin thanks for pointing that out. The awk command should work fine though, awk ignores leading spaces, but it does mess up the output =/. I post more than one solution with an explanation so readers know what tools are available and what the command actually means, so that if I make a mistake, it'll at least be easier for them to figure out what the mistake was.

[Sorin]

@AlaaAli, let's be frank, you didn't post any solution, after 5 edits they are still barely functional. AWK was not designed for this kind of work and has no place here, sed has a in-place editing flag (-i), you should use character classes in the regexp, cut can cut based on chars positions so the entire sed|cut stuff can be written as cut -c5- <file >newfile. The list can go on.

[Alaa Ali]

@Sorin yeah, using cut -c5 is the best solution because all codes copied from the internet will have the same number of leading spaces -_-. If you don't like the answer, downvote it. If you think it can be improved, edit it. If you think you have a better solution, post it.

[Sorin]

@AlaaAli, hopefully anyone using this site would have the brains to understand the example and chose the correct number of chars to cut of. Anyway, instead of trying to BS me, you might try to improve your answer.

[Jacob Vlijm]

nice! It is ctrl+alt (alt only grabs/moves the window on Ubuntu)