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--- using_grep [2016/09/06 19:34] – walkeradmin
+++ using_grep [2023/03/09 22:35] (current) – external edit 127.0.0.1
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 ====== Using GREP ======
+<color darkorange>2016</color>
+\\
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@@ Line 80: / Line 82: @@
     grep -v bar /path/to/file
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+\\
+===== UNIX / Linux pipes and grep command =====
+grep command often used with shell pipes. In this example, <color red>show the name of the hard disk devices:</color>
+\\
+    dmesg | egrep '(s|h)d[a-z]'
+    [    2.535530] sdhci: Secure Digital Host Controller Interface driver
+    [    2.539697] sdhci: Copyright(c) Pierre Ossman
+    [    2.542163] sdhost: log_buf @ bac46000 (fac46000)
+    [    2.619698] mmc0: sdhost-bcm2835 loaded - DMA enabled (>1)
+    [    2.691142] sdhci-pltfm: SDHCI platform and OF driver helper
+    [    6.716496] bcm2835-wdt 3f100000.watchdog: Broadcom BCM2835 watchdog timer
+    [    7.186573] brcmfmac: brcmf_sdio_drivestrengthinit: No SDIO Drive strength init done for chip 43430 rev 1 pmurev 24
+\\
+Display cpu model name:
+\\
+    cat /proc/cpuinfo | grep -i 'Model'
+    model name      : ARMv7 Processor rev 4 (v7l)
+    model name      : ARMv7 Processor rev 4 (v7l)
+    model name      : ARMv7 Processor rev 4 (v7l)
+    model name      : ARMv7 Processor rev 4 (v7l)
+\\
+However, above command can be also used as follows without shell pipe:
+\\
+    grep -i 'Model' /proc/cpuinfo
+\\
+\\
+===== How do I list just the names of matching files? =====
+Use the -l option to list file name whose contents mention main():
+\\
+    grep -l 'main' *.c
+\\
+\\
+===== Force grep to display output in colours =====
+Finally, you can force grep to display output in colors, enter:
+\\
+<color red>Raspbian seems to do this by default</color>
+\\
+    grep --color pi /etc/passwd
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